Clients amended template (7)
I believe the answer is:
stencil
'template' is the definition.
(I've seen this before)
'clients amended' is the wordplay.
'amended' is an anagram indicator.
'clients' with letters rearranged gives 'STENCIL'.
(Other definitions for stencil that I've seen before include "Clients (anag)" , "means of decoration" , "Make patterns using thin perforated sheets" , "Sheet with holes used to make ink or paint patterns" , "Cut-out for painting patterns or shapes" .)