POST - https://subscribercrmapi-dev.galapagosconservation.org.uk/api/groupmember

Updates or Add an existing Group Member.

{
"Id": 1,
"GroupId": 1,
"ContactId": 1234,
"DateFrom": "2025-06-23T00:00:00+00:00",
"DateTo": null,
"OfficeId": 2,
"StatusId": 3,
"Reason": ""
}