Put out when it's time to go back (4)
I believe the answer is:
emit
'put out' is the definition.
(I've seen this in another clue)
'it's time to go back' is the wordplay.
'time' anagrams to 'EMIT'.
However, I'm unsure how the anagram is indicated.
'when' is the link.
Can you help me to learn more?
(Other definitions for emit that I've seen before include "Exhale" , "shed" , "Send forth" , "Come out!" , "Send out in time" .)