Reportedly standing in line, helping with lines? (6)
I believe the answer is:
cueing
'helping with lines?' is the definition.
(as in giving an actor a cue)
'reportedly standing in line' is the wordplay.
'reportedly' indicates a 'sounds like' (homophone) clue.
'standing in line' becomes 'queuing' (a queue is a line of people).
'queuing' sounds like 'CUEING'.
(Other definitions for cueing that I've seen before include "Bringing in (an actor)" , "Prompting, actor perhaps" , "Signalling actor to speak" .)