Perhaps Michael originally made a switch to enter both sides (9)
I believe the answer is:
archangel
'perhaps michael originally' is the definition.
I can't tell whether this defines the answer.
'a switch to enter both sides' is the wordplay.
'switch' becomes 'change' (synonyms).
'to enter' is an insertion indicator.
'both sides' becomes 'rl' (I've seen this in other clues).
'change' placed inside 'rl' is 'rchangel'.
'a'+'rchangel'='ARCHANGEL'
'made' acts as a link.
Can you help me to learn more?
(Other definitions for archangel that I've seen before include "foreign port" , "Russian port on the White Sea" , "Russian city" , "Port in northern Russia, or senior heavenly messenger" , "Highest ranking member of the celestial hierarchy" .)