Legal, so goes first to request (7)
I believe the answer is:
solicit
'to request' is the definition.
(I know this)
'legal so goes first' is the wordplay.
'legal' becomes 'licit' (similar in meaning).
'goes first' says to put letters next to each other.
'licit' after 'so' is 'SOLICIT'.
(Other definitions for solicit that I've seen before include "Beg - hustle" , "Ask (favour)" , "Petition - importune" , "Make request (for business etc)" , "Ask (someone) for something" .)