Show containing rears ends in cancellation (8)
I believe the answer is:
reversal
'cancellation' is the definition.
(thesaurus)
'show containing rears ends' is the wordplay.
'show' becomes 'reveal' (revealing is a kind of showing**).
'containing' indicates putting letters inside.
'ends' says to hollow out the word (remove centre letters).
'rears' with its middle taken out is 'rs'.
'reveal' enclosing 'rs' is 'REVERSAL'.
'in' is the link.
(Other definitions for reversal that I've seen before include "A turning back" , "change for the worse" , "switch" , "A change to an opposite direction" , "that doesn't affect mum or dad" .)