Increase offer, partly, to reduce intensity (4,3)
I believe the answer is:
ease off
'reduce intensity' is the definition.
'ease off' can be an answer for 'reduce' (I've seen this before). I am unsure of the 'intensity' bit.
'increase offer partly' is the wordplay.
'partly' says the answer is hidden in the clue (part of the clue is used).
'EASE OFF' can be found hidden inside 'increase offer'.
'to' is the link.
Can you help me to learn more?
(Other definitions for ease off that I've seen before include "Slow down" , "Let up" , "Slacken gradually" , "reduce tension" , "Moderate, slacken" .)