How do you add an associated organization to a contact using REST API?

1

I have an existing contact and want to add an organization to the contact’s “Associated company(ies)”. I tried to use the following REST API endpoint:

/api/contacts

I used the PUT method to send the following body payload:

{
“id”: “307f4f05-6bb8-4827-bffc-9ea45ca927ae”,
“associatedOrganizations”: [
“a59aea58-43c9-441b-9947-a9e00afa9296”
]
}

This ended up completely deleting my contact. And it return a “204 No Content” response – apparently because the contact had gotten deleted and there was no contact content to return. The admin portal UI confirmed that it blew away my contact.

Two questions:

How do I modify the associatedOrganizations lists via REST API?

For that matter, how do I update any single contact field via the REST API?