Gave a straight decision? (5)
I believe the answer is:
ruled
'gave a straight decision?' is the definition.
The answer and definition can be both related to change as well as being past participle verbs.
Perhaps there's a link between them I don't understand?
This is all the clue.
Can you help me to learn more?
(Other definitions for ruled that I've seen before include "Reigned - lined - decided" , "Held the reins" , "Reigned or ordered" , "(Of writing paper) having printed lines" , "Exercised control over" .)