How MSPs Sell Hosted Voice to Existing IT Clients
Tom Reed · Updated 4 November 2026
The easiest place for an MSP to sell hosted voice is its own client list: they already trust you with their IT, and their phone system is often the last piece you don't manage. Start with clients who have an old on-site PBX, a contract renewal coming up, or staff working from home, offer a short trial on a few users, and move them over once the trial proves the call flows work. With SessionPBX you can run each client's phone system yourself, either self-hosted on your own servers or hosted by SessionTalk.
MSP marketing often focuses on winning new clients. This guide is about how to sell VoIP to the clients you already have. It assumes you've decided voice is worth adding (if not, start with should your MSP add hosted PBX and voice services) and that you've picked a business model (see VoIP reseller vs referral agent models). What follows is the go-to-market inside your existing client base: which clients to approach first, how to start the conversation, how to run a trial, and how to turn it into a rollout.
Why sell voice to clients you already support?
Because the hard part of any sale, trust, is already done. You know each client's network, their users and the devices they work on. When something breaks, they already call you. In many of those accounts the phone system is the one piece of technology you don't look after, and it's often the one that causes the most frustration: calls that ring the wrong person, a reception menu nobody can change, or staff who can't take calls when they work from home.
Adding voice to an existing account is less a new sale than an extension of a relationship that already works. The client gets hosted VoIP for business from a supplier they already know: one supplier for IT and phones, one bill and one support number to call. You get a recurring line on the account and a better view of how the business actually communicates.
It's also good MSP marketing that doesn't feel like marketing, and a steady route to MSP growth that starts from accounts you already hold. A well-run voice rollout gives you something concrete to talk about in account reviews, and it makes the case for voice to the next client on your list. The key is to treat it as advice, not a pitch: you're solving a problem you've probably already heard about.
Which existing clients should you approach first?
Not every client is ready to change their phone system right now, and you don't need to approach them all at once. Look for a trigger: a reason the phone system is already on their agenda. These are the situations where the conversation tends to start itself.
| Client situation | Why voice fits now | First step |
|---|---|---|
| Old on-site PBX nearing end of life | Replacement is already on their agenda | Offer a trial alongside the hardware conversation |
| Phone contract renewing in the next few months | A natural decision point | Map users and call flows before renewal |
| Remote or hybrid staff | Desk phones don't follow people home | Pilot the desktop and mobile apps with remote users |
| Office move or new site | New cabling and lines are being planned anyway | Plan the cutover with the move date |
| Complaints about missed or badly routed calls | Call flows can be fixed in the portal | Review the reception call flow in the trial |
| Copper line or ISDN reliance (UK) | PSTN switch-off is forcing a change | Share our guide to the PSTN switch-off for small businesses |
Start with the clients where you have a trigger and a good relationship with the decision-maker. One successful rollout in a friendly account is worth more than a handful of half-hearted conversations.
Before you raise it with anyone, gather what you already know. Much of this is probably in your documentation or ticket history.
Pre-call checklist
- Number of users who make and take calls
- Current numbers and carrier
- Main call flows, especially how reception and out-of-hours calls are handled
- Devices people use: laptops, phones and tablets
- Who the client's admin or decision-maker is for phones
- Renewal dates for the current phone contract and any on-site system support
How do you start the conversation?
The best place is a meeting you already have. Raise voice in a regular account review or technology planning session, alongside the rest of their IT roadmap, rather than as a separate sales call. Keep it advisory: describe what you've noticed, then what you could do about it.
A few talking points that land well with existing clients:
- One bill and one support number: you. Their phones join the rest of the IT you already look after, so there's no separate supplier to chase when something goes wrong.
- Apps on every device. Staff can call from Windows, macOS, iOS and Android, so their extension follows them between the office, home and the road.
- They keep their own carrier. SessionPBX is a bring-your-own SIP trunk phone system, so the client can keep a SIP trunk from any SIP-compliant carrier and pay their carrier directly for numbers and calls.
- Their logo on the apps. With app logo branding, the softphones their staff use show a logo and in-app product name, applied inside the standard app at runtime, so there's no app-store wait.
Listen more than you talk. If the client mentions missed calls, a reception menu they can't change or staff who can't answer from home, that's your opening to suggest a trial.
How should you run a trial for an existing client?
A trial removes most of the risk for the client, and for you. On the SessionPBX Partner Programme, new partner customer tenants receive a 30-day trial on hosted and self-hosted deployments, subject to your concurrent trial allowance. A partner administrator must explicitly purchase the subscription to continue service. Nothing carries on into a paid subscription without your decision.
Keep the trial small and focused:
- Pick a pilot group. A few users who make and take calls every day, ideally including someone who works remotely.
- Include the main reception call flow. That's what the client will judge the system on. Rebuild their opening hours, menu and ring order so they can hear the difference.
- Install the apps the way you would at rollout. Desktop and mobile apps, set up by QR code or setup link, so you test the real onboarding process too.
- Agree what success looks like up front. For example: calls reach the right people, voicemail arrives by email, and the pilot group is comfortable with the apps.
- Book a review before the trial ends. Walk through what worked, what needs changing and what a full rollout involves.
For a fuller list of what to check during a trial, see the hosted PBX free trial checklist.
How do you move from trial to a full rollout?
Once the trial has proved the call flows work, the rollout is mostly organisation. On SessionPBX, each customer gets their own SessionPBX project under your partner account. You create it, you own it, and you manage extensions, numbers, the SIP trunk and call flows for that customer. The numbers and the trunk itself come from the client's chosen carrier: you connect the client's own SIP trunk by IP or by credentials and decide where each call goes.
Users don't need to type SIP settings. Invite them by email, and they set up the mobile apps with a QR code or the desktop apps with a setup link. For an existing client, that means you can schedule the rollout around their working day instead of visiting every desk.
Rollout checklist
- Confirm the final user list and extensions
- Connect the client's SIP trunk from their chosen carrier
- Publish the reception call flow tested in the trial
- Set up voicemail and missed-call notifications by email
- Invite users and send setup emails with the QR code or setup link
- Agree a cutover date with the client and their carrier
- Tell staff who to call for help: you
For the full per-customer runbook, see the MSP customer onboarding guide for hosted PBX. For the app side, our guide to rolling out desktop softphones covers Windows and Mac deployment.
Hosted or self-hosted: which suits an existing client base?
SessionPBX gives you both options, and partner pricing applies to both hosting options.
Self-hosted. If you already run your own infrastructure, you can self-host SessionPBX on your own servers and run many customer tenants with multi-tenant, with every customer kept separate. That suits MSPs and IT resellers that want their clients' phone systems on infrastructure they control, alongside the other services they host. Self-hosted is available to approved partners only. For how running many clients side by side works, see multi-tenant PBX for MSPs.
Hosted by SessionTalk. If you'd rather have nothing to run, put clients on SessionPBX hosted by SessionTalk. SessionTalk hosts and maintains it in the UK (London), the US (New York) or Singapore, and you choose where each customer is hosted. Each client still gets their own project, created and owned by you.
You can also mix the two: hosted for smaller clients, self-hosted where you want the system on your own infrastructure. Either way, you manage each client's users and call flows the same way, and the apps are the same on Windows, macOS, iOS and Android.
What should you agree before you price it?
Agree the scope before you put a number in front of the client: how many users, which plan fits their call handling, whether they want their logo on the apps, and who supports what. With SessionPBX you set your own price and invoice your customer, so how you package and price voice is your decision. For the pricing thinking, see how to price VoIP as an MSP, and for bundling voice with your existing services, see packaging hosted PBX for MSPs and telecom resellers.
FAQ
Do my clients have to change their phone carrier?
No. SessionPBX is a bring-your-own SIP trunk phone system, so it works with a SIP trunk from any SIP-compliant carrier, connected by IP or by credentials. Your client can keep a carrier they already use or choose a new one, and their carrier bills for numbers and calls. Internal calls between team members are included.
Can my clients see my logo on the apps?
Yes, with app logo branding. Your logo and in-app product name appear on the softphones on Windows, macOS, iOS and Android. It's included on Teams Business and available as an add-on on Teams Phone. Teams Phone and Teams Business are SessionPBX plan names; SessionPBX isn't related to Microsoft Teams.
How long can a client trial it?
New partner customer tenants receive a 30-day trial on hosted and self-hosted deployments, subject to your concurrent trial allowance. A partner administrator must explicitly purchase the subscription to continue service. Use the trial for a small pilot group and the main reception call flow, so the client sees how calls will really work.
Can I run it on my own servers?
Yes. Approved partners can self-host SessionPBX on their own servers and run it multi-tenant, with many client tenants on one platform and every customer kept separate. If you'd rather not run anything, SessionTalk hosts and maintains it in the UK (London), the US (New York) or Singapore instead.
Who bills the client?
You do. You set your own price and invoice your customer on your own terms. SessionTalk bills your partner organisation for each customer subscription, and there are no commissions to chase and no payouts to wait for. That keeps the client relationship, the contract and the billing with you, alongside the rest of their IT.
What apps do users get?
Users get the softphone apps your clients' staff use on Windows, macOS, iOS and Android. They set up the mobile apps by scanning a QR code and the desktop apps with a setup link, so nobody types SIP settings. The same account works across their devices, from the office to home.
Ready to offer voice to the clients you already support? Apply to the SessionPBX Partner Programme. You don't need a portal account to apply, and every application is reviewed by our team. If you'd like to see the product first, look at the hosted PBX for your clients.
