Team's head managed with referee's backing to switch teams (8)
I believe the answer is:
transfer
'switch teams' is the definition.
(as in a football transfer)
'team's head managed with referee's backing' is the wordplay.
'head' says to take the initial letters.
'managed with' becomes 'ran' (I've seen this in another clue. I am not sure about the 'with' bit.).
'referee's' becomes 'ref's' ('ref' can be a synonym of 'referee').
'backing' is a reversal indicator.
The first letter of 'teams' is 't'.
'refs' written backwards gives 'sfer'.
't'+'ran'+'sfer'='TRANSFER'
'to' acts as a link.
(Other definitions for transfer that I've seen before include "Move from one team to another" , "a side to side movement in soccer, perhaps" , "Star fern (anag.)" , "Reassign" , "Extremely stiff in coach, I must leave conveyance" .)