What happens to the Vicar of Christ when Jesus Christ returns?

The Pope is the Vicar of Christ according to the Catholic church. > A vicar (/ˈvɪkər/; Latin: vicarius) is a representative, deputy or > substitute; anyone acting "in the person of" or agent for a superior > (compare "vicarious" in the sense of "at second hand"). According to Papal teachings, what happens to the Pope when Jesus Christ returns? What if the Pope (who is human and can/does make mistakes) doesn't believe that he has returned?