Performance in the theatre switched to open air (9)

I believe the answer is:

operation

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'performance in the theatre' is the definition.
'operation' can be an answer for 'performance' (synonyms). I'm unsure of the 'in the theatre' bit.

'switched to open air' is the wordplay.
'switched' is an anagram indicator (letters switch places).
'to'+'open'+'air'='toopenair'
'toopenair' is an anagram of 'OPERATION'.

Can you help me to learn more?

(Other definitions for operation that I've seen before include "working" , "financial transaction" , "running" , "To one pair (anag.)" , "Theatre procedure" .)

I've seen this clue in The Globe and Mail.

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