Colleague has a Gmail/Google account that needs to have the Recovery Phone number changed.

He has 2-step authorisation active, and the Two-step Authorisation telephone number correct, just the Recovery number is an old one that is no longer in use.

Every time he goes to change anything, the system asks for the old Recovery Number!

Does anyone know if de-activating 2-step authorisation will in fact allow the change of the Recovery number?

Else, what does one do?