Do you mean superficially? You'd have to go to the Global Game Options window (opened by the...yellow piece of paper?) -> Edit City Names. Select Baltimore in the 'Choose City' dropdown, then enter the new name and abbreviation.
It won't really be Memphis - if that last move to Baltimore was in-game, the city will still show as being in MD, it will be the same fan support and stadium, etc. - but that's the best you can do.
(want list for FOF14 - a way for commissioners to edit city attributes (pop, affluence) and/or be able to change the city affiliations once a career starts)
__________________
null
|