Waiter set wrong charge (7)
I believe the answer is:
steward
'waiter' is the definition.
(I've seen this before)
'set wrong charge' is the wordplay.
'wrong' indicates an anagram.
'charge' becomes 'ward' (I've seen this before**).
'set' is an anagram of 'ste'.
'ste'+'ward'='STEWARD'
(Other definitions for steward that I've seen before include "Attendant on plane or ship" , "Crowd-control official" , "race course official" , "Attendant on ship - race official" , "Ship/aircraft worker" .)