Searches for small seat, briefly to be brought back after first rehearsal (5)
I believe the answer is:
roots
'searches' is the definition.
(I've seen this before)
'small seat briefly to be brought back after first rehearsal' is the wordplay.
'small seat' becomes 'stool' (I've seen this before).
'briefly' means to remove the last letter.
'to be brought back' says the letters should be written backwards.
'after' is a charade indicator (letters next to each other).
'first rehearsal' becomes 'r' (1st letter of 'rehearsal').
'stool' with its last letter removed is 'stoo'.
'stoo' reversed gives 'oots'.
'oots' after 'r' is 'ROOTS'.
'for' acts as a link.
(Other definitions for roots that I've seen before include "authentic music" , "Genealogy" , "Cultural origins" , "Antecedents" , "Radicals" .)