Gave evidence when the date is changed about the trial (8)
I believe the answer is:
attested
'gave evidence' is the definition.
The definition and answer can be both to do with communicating as well as being past participle verbs.
Perhaps you can see a link between them that I can't see?
'the date is changed about the trial' is the wordplay.
'is changed' indicates anagramming the letters.
'about' indicates putting letters inside.
'the trial' becomes 'test' ('test' can be a synonym of 'trial').
'date' anagrammed gives 'ated'.
'ated' enclosing 'test' is 'ATTESTED'.
'when' is the link.
Can you help me to learn more?
(Other definitions for attested that I've seen before include "Provided evidence" , "Declared that something was true" , "Affirmed to be true" , "Provided proof" , "Confirmed" .)