It's a big improvement on the old pan (4-4)
I believe the answer is:
face-lift
'old pan' is the definition.
Although both the answer and definition are verbs in their base form, I can't see how they can define each other.
'it's a big improvement on the' is the wordplay.
I cannot really see how this works, but
'a' is within the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found within the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for face-lift that I've seen before include "Cosmetic surgery to remove wrinkles" , "Popular form of cosmetic surgery" , "Elevation of visage in cosmetic surgery" , "Cosmetic operation of elevated nature" , "Cosmetic procedure" .)