Given material backing? (5)
I believe the answer is:
lined
'given material backing?' is the definition.
The definition and answer can be both related to change as well as being past participle verbs.
Perhaps they are linked in a way I don't understand?
'given material' is the wordplay.
I cannot really see how this works, but
'material' could be 'line' (line is a kind of material) and 'line' is located in the answer.
A single letter 'd' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for lined that I've seen before include "Covered inside" , "Put in a row" , "What ruler did" , "Covered inner surface" , "displaying signs of age" .)