Letter of authorization
LOA / porting letter of authorization / number porting authorization
A letter of authorization is the signed form that lets a new phone provider request a business's existing numbers from the current provider, a move called porting. If its details do not match the old carrier's records, the port is usually rejected and the move is delayed.
Porting moves a business phone number to a new provider, which sends the request to the old provider for approval or rejection. The letter of authorization is the customer's signed permission for that request. In a simple port, the order sent to the old carrier includes one check box confirming the new provider is the customer's agent and has an authorization on file.
In Microsoft Teams, the authorized user on the old account can sign electronically for US and Canadian numbers. Any supported market accepts an uploaded signed letter. The authorized user cannot be changed during the request.
Microsoft calls mismatched information the most common cause of errors and delays. In the United States the record to match is the Customer Service Record, which a business can request at any time. Ports on one account number go one at a time. Overlapping requests are rejected after the first, and requests sent at the same moment can all be rejected.
For a simple port, the old carrier may require only 14 standard data fields, such as account number and zip code. A passcode is optional unless the customer asked for and was assigned one. The FCC's definition, as a 2010 law firm summary and CenturyLink's wholesale guide describe it, covers a single line account with no unbundled network elements, complex switch translations such as Centrex, or reseller. In 2010 the FCC said whether to modify that definition was pending. Ports from multi-line accounts are non-simple, and the field limit does not cover them.
A simple port between landlines, or between a landline and a mobile line, must be done within one business day. Simple ports involving VoIP get the same, and the new provider or customer can ask for longer. Carriers with an FCC waiver get four business days for simple ports, and non-simple ports also get four. These intervals do not cover ports between two mobile carriers. A complete, accurate simple port request received from 8 a.m. to 1 p.m. in the porting region's main time zone is eligible for activation that midnight.
The federal clock starts when the old carrier receives an accurate, complete request. Microsoft's process typically takes 7 to 14 days, or up to 30 with some providers, and includes steps before the request reaches the old carrier.
In practice
A landscaping company moves its main number and several staff lines on one landline account, to Microsoft Teams. The port is non-simple, so the 14-field limit does not apply and the four business day interval does. The office manager, who is the authorized user, signs with the trading name, but the account is under the legal company name and has a freeze. The rejection gives only a categorical reason. The company pulls its Customer Service Record and fixes the name. The office manager orders the freeze removed, which Microsoft says can take one to three weeks. On resubmission, the old carrier's response clock starts over.
Not the same as
- Letter of agency (preferred carrier change)
- In the FCC's carrier change rules, a letter of agency authorizes a change of a subscriber's preferred carrier and must list the billing name, address and each number covered. That section of the rules does not mention porting a number to a new provider.
- Customer Service Record
- The Customer Service Record is the old carrier's official record of the account. The letter of authorization is the customer's signed permission for the port, and its details must match that record.
Why it matters to you
An inactive or disconnected number cannot be ported, so the old service stays on until every number has moved. Pulling the Customer Service Record first and porting one batch per account at a time remove two avoidable causes of rejection.
What to ask or check
- 01Does your letter of authorization match the old carrier's Customer Service Record exactly, including name, service address and account number?
- 02Who is the authorized user on your current phone account, and can that person sign?
- 03Is there a freeze or account PIN on your account, and who can remove or supply it?
What people get wrong
That the new provider always knows why a port was rejected. Microsoft says the old carrier passes it only the categorical reason, and when corrected information is needed, the customer has to work it out directly with that carrier.
Red flags
- Advice to cancel the old phone service before the port request is submitted. Inactive or disconnected numbers cannot be ported.
- A letter of authorization signed by someone who is not the authorized user on the old account.
- Several port requests for numbers on the same account number submitted at the same time.