Dismiss assembly and switch off (4,3)
I believe the answer is:
turn out
This clue is a triple definition!
'dismiss' is the first definition.
(I've seen this before)
'assembly' is the second definition.
(I've seen this before)
'and' is a link.
'switch off' is the third definition.
(I know that switch off can be written as turn out)
(Other definitions for turn out that I've seen before include "A number at meeting" , "assembly" , "Dismiss" , "End up" , "All the voters" .)