Syncing accounts

[Frag-Owt35]

I have an old city synced to my facebook that i no longer use. How do i unsync that city to sync my current one?

[Sparkin75]

I can not sync my account to Facebook.  I've gone into facebook and removed the game from "apps and websites". I have deleted my SIM app and reinstalled. I continue to get the same message.  " Sorry Mayor! This account is already linked to another city. We cannot log you into this account."  I have attached 2 screen shots, one asking me to "Continue as Michael" and the other is the error screen.  My gmail is [edit: email address removed]