Reserve permit for small publication (7)
I believe the answer is:
booklet
'small publication' is the definition.
(I've seen this before)
'reserve permit' is the wordplay.
'reserve' becomes 'book' (booking is a kind of reserving).
'permit' becomes 'let' (synonyms).
'book'+'let'='BOOKLET'
'for' is the link.
(Other definitions for booklet that I've seen before include "Pamphlet" , "Thin publication" , "minor publication" , "Short publication" , "football programme?" .)