Paper maybe not changing by the sound of it (10)
I believe the answer is:
stationery
'paper' is the definition.
(stationery is a kind of paper)
'not changing by the sound of it' is the wordplay.
'not changing' becomes 'stationary' (stationary means not moving or changing).
'by the sound of it' indicates a 'sounds like' (homophone) clue.
'stationary' sounds like 'STATIONERY'.
'maybe' acts as a link.
(Other definitions for stationery that I've seen before include "Files etc" , "Writing material" , "The papers, etc" , "Treasury tags, for instance" , "Materials needed for writing" .)