Authorisation could be, for instance, like this (3-2)
I believe the answer is:
say-so
'authorisation' is the definition.
(I know that authorisation can be written as say-so)
'for instance like this' is the wordplay.
'for instance' becomes 'say' (both can be used to introduce an example).
'like this' becomes 'so' ('like so').
'say'+'so'='SAY-SO'
'could be' is the link.
(Other definitions for say-so that I've seen before include "Authorisation" , "Authority - rumour" , "Final authority" , "Mere assertion (colloq.)" , "Authority to make or allow something to happen" .)