A tax return to distribute (5)
I believe the answer is:
allot
'distribute' is the definition.
(allotting is a kind of distributing)
'a tax return' is the wordplay.
'tax' becomes 'toll' (I've seen this in other clues**).
'return' shows that the letters should be reversed in order.
'toll' back-to-front is 'llot'.
'a'+'llot'='ALLOT'
'to' acts as a link.
(Other definitions for allot that I've seen before include "Ration" , "Dish out" , "Assign or distribute" , "Apportion (something to someone)" , "grant" .)