Change them? You get tea at Bali? No action ends? (8)
I believe the answer is:
mutation
'change' is the definition.
(mutation is a kind of change)
'you get tea at bali? no action ends?' is the wordplay.
'you' becomes 'mu' (I am not sure about this - if you are sure you should believe this answer much more).
'ends?' says to take the final letters (I've seen 'end' mean this).
The last letters of 'get tea at bali no action' are 'tation'.
'mu'+'tation'='MUTATION'
'them?' is the link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for mutation that I've seen before include "Change in genetic structure" , "Natural change process" , "Change, especially biological or genetic" , "Variant form (of gene)" , "17 change in form" .)