Reversal of roles for band (5)
I believe the answer is:
strap
'band' is the definition.
(strap is a kind of band)
'reversal of roles' is the wordplay.
'reversal of' is a reversal indicator.
'roles' becomes 'parts' ('part' can be a synonym of 'role').
'parts' in reverse letter order is 'STRAP'.
'for' acts as a link.
(Other definitions for strap that I've seen before include "Elongated leather strip" , "Length or loop, of leather perhaps" , "loopy band" , "Parts of a leather band" , "Beat; securing band" .)