Cheers, after bringing about a change: ditching unknown gaming figure (6)
I believe the answer is:
avatar
'gaming figure' is the definition.
(figure representing a player in a game)
'cheers after bringing about a change' is the wordplay.
'cheers' becomes 'ta' (both can informally mean thank you).
'after bringing about' means one lot of letters goes inside another (to bring about can mean to bring around).
'change' becomes 'var' (I can't explain this - if you can you should give a lot more credence to this answer).
'a'+'var'='avar'
'ta' inserted into 'avar' is 'AVATAR'.
'ditching unknown' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
(Other definitions for avatar that I've seen before include "Blockbuster film" , "Manifestation of a deity (Hinduism)" , "Human or animal manifestation of Vishnu" , "In Hinduism, the descent to earth of a deity" , "Person seen as embodying a particular ideal" .)