Move across to the referee standing by (8)
I believe the answer is:
transfer
'move' is the definition.
(transferring is a kind of moving)
'across to the referee standing by' is the wordplay.
'across' becomes 'trans' (prefix meaning across or over).
'to the referee' becomes 'ref' (synonyms).
'standing' says the letters should be written backwards (in a down clue, letters stand up).
'by' is a charade indicator (letters next to each other).
'ref' reversed gives 'fer'.
'trans'+'fer'='TRANSFER'
(Other definitions for transfer that I've seen before include "Move, change (to new place)" , "player's move" , "Give over!" , "Footballer maybe" , "Move something from one place to another" .)