Change reflected ups and downs in the main (4)
I believe the answer is:
tide
'main' is the definition.
(thesaurus)
'change reflected' is the wordplay.
'change' becomes 'edit' (edit can mean to change or alter).
'reflected' says the letters should be written backwards (letters reflected back).
'edit' backwards is 'TIDE'.
'ups and downs in the' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for tide that I've seen before include "Season; current" , "Ebb and flow of the sea" , "Ebber and flower?" , "Periodic flow" , "It ebbs and flows" .)