Turn to notable dignitary for backing (5)
I believe the answer is:
pivot
'turn' is the definition.
(I know that pivot is a more specific form of the action the turn)
'to notable dignitary for backing' is the wordplay.
'notable dignitary' becomes 'VIP' (Very Important Person).
'for backing' says the letters should be written backwards.
'to'+'vip'='tovip'
'tovip' back-to-front is 'PIVOT'.
(Other definitions for pivot that I've seen before include "Centre point" , "Pin, centre of revolution" , "Point about which something turns" , "Something of central importance" , "Kind of wine grape" .)