Representation changes area to old city used by pirates (4,5)

'city used by pirates' is the definition.
(Jamaican city historically used by pirates)

'representation changes area to old' is the wordplay.
I cannot quite understand how this works, but
'area' could be 'troy' (Troy is an example) and 'troy' is located in the answer.
'old' could be 'o' (common abbreviation eg in OE for Old English) and 'o' is found within the answer.
This may be the basis of the clue (or it may be nonsense).