How to switch business phone providers without losing your number

Yes, you can keep your number

Moving a phone number from one provider to another is called porting. Under the FCC's local number portability rules, US customers can generally keep their local numbers when they switch between providers in the same area, and toll-free numbers can move between providers too. Your old provider isn't allowed to hold your number hostage because you're leaving, though it can reject a port request if the details on the request don't match its records. Most porting delays come from exactly that: a mismatch in the paperwork.

So the whole game is getting the details right the first time.

The two documents that matter: CSR and LOA

Customer Service Record (CSR)

The CSR is your current provider's record of your account: the account holder's name, the service address, the account number, and the numbers on the account. When your new provider submits a port request, the old provider compares it against the CSR. If the name is spelled differently, the address is your new office instead of the one on file, or the account number is wrong, the request can be rejected.

You can usually ask your current provider for a copy of your CSR, or at least confirm the exact name, address and account number they have on file. It's worth doing before you start.

Letter of Authorization (LOA)

The LOA is a short form you sign that authorizes your new provider to move the numbers on your behalf. It lists the numbers being ported and repeats the account details from the CSR. It's signed by someone authorized on the account, typically the account holder or an owner of the business.

What to gather before you start

• A recent bill from your current provider. It shows the account number, billing name and often the service address.
• Every number you want to keep: main lines, direct lines, fax numbers and toll-free numbers. Don't forget numbers that only forward somewhere.
• The account holder's name and the service address, exactly as your provider has them.
• Your account PIN or passcode, if your provider uses one. Mobile carriers in particular usually require a separate port-out PIN, which you can request from them.
• The authorized person who will sign the LOA.

Step by step: how a port works

1. Sign up with the new provider, but don't cancel the old one. This is the most important rule in porting. If you cancel your old service first, the numbers can be disconnected and may be very hard, or impossible, to get back.
2. Submit the port request. Your new provider files the request with your LOA and account details.
3. The old provider validates it. They check the request against the CSR. If something doesn't match, they reject it and say why, and the request is corrected and resubmitted.
4. You get a date. Once the request is accepted, the old provider confirms a date for the switch, often called the FOC (Firm Order Commitment) date.
5. Your new system is built and tested in the meantime. Users, extensions, call flows, voicemail and greetings can all be set up before the port, often using a temporary number for testing.
6. Port day. On the scheduled date the numbers move. Calls start arriving at the new system, sometimes after a short period where calls route inconsistently while carriers update their records.
7. Confirm, then cancel. Make test calls from a cell phone and from another carrier if you can. Once calls to every ported number arrive correctly, cancel any remaining service with the old provider.

How long does porting take?

It depends on the type of number and the providers involved. Simple ports of a few local numbers can complete in days, while larger or more complex ports, such as many numbers, numbers spread across several accounts, or some older landline setups, can take a few weeks. Toll-free numbers follow their own process. Ask your new provider for an estimate after they've seen your bill, and plan your switch so you're not up against a hard deadline such as a lease ending or a contract renewing.

Common reasons ports get rejected

• The business name on the request doesn't match the CSR (for example, a DBA versus the legal name).
• The service address is the new location instead of the address on file.
• A missing or wrong account number or PIN.
• The request includes numbers from a different account, or leaves out a number that the provider requires to be ported together with the main line.
• The LOA was signed by someone who isn't authorized on the account.

None of these are disasters. They just cost time, which is why checking the CSR details first pays off.

Partial ports and what's left behind

You don't have to move every number. Porting some numbers and keeping others is called a partial port. Be clear about which lines, if any, stay with the old provider, because the remaining account may change (for example, a new main number may need to be assigned). If you're moving everything, plan to cancel the old account only after every number has moved.

Porting doesn't move things like your old voicemail messages, phone menus or call-forwarding rules. Those get rebuilt on the new system, so it helps to write down how your calls are handled today: who answers, what the menu says, where calls go after hours.

Don't forget 911

With an internet-based phone system, each number needs a registered service address so 911 calls route to the right emergency center and show your location. When you switch, confirm the 911 address for each line, especially if people work from more than one location.

Avoiding downtime

• Keep the old service active until the port is complete and tested.
• Have the new system fully built before port day, so calls have somewhere to go the moment they arrive.
• Pick a port date away from your busiest day of the week.
• Install the mobile app on your team's phones ahead of time as a backup way to answer.