Raised energy in regime change (4)
I believe the answer is:
edit
'change' is the definition.
(editing is a kind of changing)
'raised energy in regime' is the wordplay.
I cannot really understand how this works, but
'energy' could be 'e' (physics symbol as in E=mc2) and 'e' is located in the answer.
The remaining letters 'dit' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
(Other definitions for edit that I've seen before include "Manage a newspaper" , "Be in charge of (newspaper)" , "Check text for publication" , "Make changes to (text)" , "Revise text" .)