Hi Scott!
I looked into the error you were receiving and found that it was due to requesting an update to the end time of an occurrence in a series event without specifying a start time. Your request format is sound and you should receive a successful response, as well as see the event updated accordingly, if you include a start time in your request.
curl --include \
--request POST \
--header "Authorization: Bearer PERSONAL_OAUTH_TOKEN" \
--header "Content-Type: application/json" \
--data-binary "{
\"event\": {
\"start\": {
\"timezone\": \"America/Phoenix\",
\"utc\": \"2021-12-01T19:00:00Z\"
},
\"end\": {
\"timezone\": \"America/Phoenix\",
\"utc\": \"2021-12-01T21:00:00Z\"
}
}
}
Hopefully this is helpful!
Thanks,
Natalie