Agent about to stage musical from the East (14)
I believe the answer is:
representative
'agent' is the definition.
(thesaurus)
'to stage musical from the east' is the wordplay.
'to' becomes 're' (I am not sure about this - if you are sure you should believe this answer much more).
'stage' becomes 'present' (present can mean to stage or put on).
'musical' becomes 'evita' (Andrew Lloyd Webber musical).
'from the east' shows that the letters should be reversed in order (on a map from right to left).
'evita' reversed gives 'ative'.
're'+'present'+'ative'='REPRESENTATIVE'
'about' acts as a link.
(Other definitions for representative that I've seen before include "US politician" , "MP" , "delegate" , "member of parliament, perhaps" , "typical example" .)