Happen to change course (4,5)

I believe the answer is:

come about

I believe this is a double definition.

'happen' is the first definition.
(synonyms)

'change course' is the second definition.
(thesaurus)

'to' is the link.

(Other definitions for come about that I've seen before include "turn?" , "Happen - to change course in yacht" .)

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

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