Twostep verification

Hi @bluescorer, we understand your concern about 2-Factor Authentication, in which a code is sent to your old cell phone number. Let's get the help you need.

We recommend that you try these steps to see if it allows you to add the new phone number:

1. Access att.com and select the Person icon from the upper, right-hand corner.
2. Click View Profile > Contact Info > Phone tab. 
3. Edit the myAT&T Wireless Number.
4. Update the wireless number with a valid AT&T contact cell number.

• You must complete the device validation and the contact number must age 30 days before it's eligible to receive the verification code.
• The myAT&T Wireless Number has to be aged 30 days before it is an option for Trusted Sign In (2FA) verification.
•  You can only assign your wireless number to one user ID. If your wireless number is already assigned to an ID, delete it from that ID before you can assign it to a different ID.
• The assigned wireless number must be an AT&T wireless number; it can't be the phone number for Digital Phone, Landline Home Phone, or AT&T PREPAID.

Let us know how it goes!

Thank you for contacting AT&T Community Forums.

Jasmine, AT&T Community Specialist

Thanks for your help.
I do not have any cell phone.