Don't go out with marine (6)
I believe the answer is:
remain
'don't go' is the definition.
The answer and definition can be both related to change as well as being verbs in their base form.
Maybe you can see a link between them that I can't see?
'with marine' is the wordplay.
'marine' can be anagrammed to 'REMAIN'.
Though, I am not sure how this is indicated.
'out' acts as a link.
Can you help me to learn more?
(Other definitions for remain that I've seen before include "Stay, don't go" , "Survive" , "Continue in position" , "Airmen (anag.)" , "Stay behind" .)