Learn a new skill on set (7)
I believe the answer is:
retrain
'learn' is the definition.
(I know that retrain is a more specific form of the action prepare)
'a new skill on set' is the wordplay.
I cannot quite understand how this works, but
'a' is present in the answer.
'new' could be 'n' (common abbreviation eg NT for New Testament) and 'n' is found in the answer.
'on' could be 're' ('on' can be mean 'with reference to') and 're' is found within the answer.
The remaining letters 'tri' is a valid word 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 retrain that I've seen before include "Prepare for new job" , "Terrain (anag.)" , "Take refresher course" , "ready for a new assignment" , "coach yet again" .)