Withdraw actual line about to be introduced (6)
I believe the answer is:
recall
'withdraw' is the definition.
(synonyms)
'actual line about to be introduced' is the wordplay.
'actual' becomes 'real' (similar in meaning).
'line' becomes 'l'.
'about' becomes 'c' (abbreviation for 'circa').
'to be introduced' indicates putting letters inside.
'real'+'l'='reall'
'reall' placed around 'c' is 'RECALL'.
(Other definitions for recall that I've seen before include "Summon back - ability to remember" , "Hark back" , "cancel" , "Evoke" , "order to come back" .)