Hello @Ernest Cook !
In case you CAN login bypassing Authenticator with an SMS or other method
go to aka.ms/MFASetup
There you can change the method .Sign out other devices and in general re apply the Registration process by adding Sign_in methods
In case you cannot login due to MFA , unfortunately someone has to disable MFA and re register your new device. In general two methods at least can save you from the burden!
I hope this helped , so kindly mark the answer as Accepted if indeed you got the info you needed
Otherwise reply here with details so we can provide answers as well
Best regards!