Switching PBX providers without losing your business number

It’s the fear that holds back the most PBX switches, and it’s not a silly fear: your business number has been on your website, your invoices, your van signage, and in your customers’ contacts for years. Losing it would be far worse than putting up with a mediocre provider. The good news is you won’t lose it: the number is yours, not the carrier’s, and you can take it elsewhere. The part that does deserve attention is what happens to your calls during the process.

The number is yours, and that’s the law

Portability is a recognized right: you can switch carriers while keeping your numbering, and your current carrier can’t refuse or attach conditions to it. The only situation that blocks a port is unpaid invoices or a minimum-term contract still in effect, and even that doesn’t prevent porting: it just means paying the agreed penalty.

Worth knowing, because the moment you announce you’re leaving, a retention call with an offer you were never given before tends to show up. The fact that it comes now and not earlier says quite a bit about the relationship.

What you need before you start

Have this ready and the process won’t get stuck:

• A recent invoice from your current carrier, with the exact account holder and tax ID.
• The complete list of numbers you want to port. This is where things most often go wrong: forgotten lines, the accounting department’s fax, or a number only one department uses almost always turn up.
• The correct account holder. If the line is registered under a previous legal entity, a partner, or someone no longer at the company, this needs sorting out first. It’s the number-one cause of rejected ports.
• Real contact details for someone who can make decisions during the process.

What happens to calls in the meantime

This is the one part that carries real risk, which is why it’s worth understanding.

Porting happens in a specific window, usually overnight. At that point the number stops being on the old carrier’s network and moves to the new one. If everything is set up on the receiving end before that window, the cutover takes minutes and happens while nobody’s calling.

The problem is usually not technical: it’s about sequencing. If you reach the porting date without the PBX fully set up at the new provider (extensions, schedules, forwarding, greetings), the number lands somewhere nothing is ready. That’s when calls actually get lost — and it’s not the porting’s fault.

That’s why the correct order is always the same: set up and test everything at the new provider first, then port the number. If anyone suggests doing it the other way around, be wary.

The five steps, in order

1. Inventory. List every number, who uses it, and where it’s published. Use this as a chance to decide which ones no longer make sense.
2. Setup at the destination. The new virtual PBX is fully configured: extensions, schedules, forwarding, menus, and recordings.
3. Testing with temporary numbering. The new provider gives you temporary numbers and you make the calls yourself. This is where issues get caught, not afterward.
4. Request and date. Porting is requested and the window is agreed. Pick your business’s lowest-traffic day and time.
5. Execution and verification. On the day itself, someone calls each number from outside to confirm it lands where it should.

The four mistakes that actually cost you calls

Cancelling the old service before porting. Never do this. If you cancel the line, the number gets released and you genuinely lose it. The old contract cancels itself automatically once porting is complete.

Forgetting a number. The one only accounting uses, the one listed in an old directory, the fax line. Check invoices from the last twelve months.

Porting on a Friday. If something goes wrong, you’ve got the whole weekend ahead of you. Tuesday or Wednesday instead.

Not notifying the team internally. If the team doesn’t know a change is happening, the first odd behavior gets read as a breakdown, and the calls to IT start.

What about mobile lines?

Yes, those too. Business mobile lines port the same way, and it’s actually the right moment to decide whether to integrate them into the PBX. If your salespeople are calling from their own mobiles, right now you have no record of those calls and no way to recover them when someone doesn’t pick up.

Integrating them is what lets the team work from anywhere while keeping the company number, with every call logged no matter where it’s made from.

How long it takes

Timelines vary depending on the type of numbering and the originating carrier, so anyone who gives you an exact figure without looking at your lines is guessing. What’s reasonable is for your provider to give you a specific date once the request is submitted, with the prior setup finished before that date.

What you can insist on: getting the date in advance, having testing done beforehand, and having someone reachable on the day of the window.

Who does the work

This is the practical difference between providers. With some, porting is a form you fill out yourself and a confirmation email. With others, someone handles the inventory, the paperwork, coordination with the originating carrier, and the follow-up verification.

At Glofera, we manage the whole thing end to end, including tracking down those forgotten numbers that always turn up. If you’re considering the switch, start with the free communications analysis: we review what numbering you have today, what’s worth porting, and what’s worth simplifying along the way.

Frequently asked questions

Can I switch PBX providers without losing my business number?

Yes. The number belongs to your company, not the carrier, and portability is a right. Your current carrier can’t refuse to release it, even with a minimum-term contract in place: in that case it still gets ported, and you pay the agreed penalty.

How long will my number be down during porting?

The execution window is short and happens during low-traffic hours, usually overnight. If the destination PBX is configured and tested before that date, the cutover takes minutes and happens while nobody’s calling.

What happens if I have a minimum-term contract with my current carrier?

A minimum term doesn’t block porting: it just means paying the penalty agreed in the contract. It’s worth calculating that in advance, since in many cases the savings from switching cover it within a few months.

Can I port the company’s mobile lines too?

Yes, and it’s the right time to decide whether to integrate them into the PBX. Integrating them lets you log every call the team makes and have them made using the company number from any device.

Do I need to cancel my current service before porting?

No, never. If the line is cancelled before porting, the number gets released and lost. The old contract cancels itself automatically once the porting process is complete.