Shanghai almost needs a port manager (10)
I believe the answer is:
impresario
'manager' is the definition.
(thesaurus)
'shanghai almost needs a port' is the wordplay.
'shanghai' becomes 'impress' ('impress' can be a synonym of 'shanghai').
'almost' means to remove the last letter (most of the word but not all of it).
'needs' is a charade indicator (letters next to each other).
'port' becomes 'rio' (I've seen this before).
'impress' with its final letter taken off is 'impres'.
'impres'+'a'+'rio'='IMPRESARIO'
(Other definitions for impresario that I've seen before include "Entertainment manager" , "Theatre promoter" , "Theatrical entrepreneur" , "opera manager" , "Sponsor and manager of public entertainments" .)