Change fibre seal — it protrudes slightly (3,6)
I believe the answer is:
bas relief
'it protrudes slightly' is the definition.
(sculptural method)
'change fibre seal' is the wordplay.
'change' indicates an anagram.
'fibre'+'seal'='fibreseal'
'fibreseal' is an anagram of 'BAS-RELIEF'.
(Other definitions for bas relief that I've seen before include "Sculpture" , "Moore may have produced this" , "work of art" , "less outstanding work" , "projected figure" .)