How to get MFA to send code to valid email address, not invalid phone number

Question

I attempt to log in, with my email address as the User Name and valid Password.
However the MFA asks to send a code to my old phone number, to authenticate.
But, I don't have that old phone number anymore.
I want MFA to send to my valid email address.

How can I change the phone number that my MFA sends to?
There should be a choice to send the code to my email address, (which I have access to), not the phone number that I don't have access to.
Please advise.