Merges one contact into another and deletes the contact that was merged. The destination contact survives and keeps its id; the source contact's lists, tags, automations, deals, notes and activity are moved onto the destination, and the source is then removed.

The merge runs synchronously, so the response means the contacts have already been merged. It cannot be undone.

Where the two contacts hold conflicting information, resolutionFieldId and resolutionAutomationId name which of the two contacts wins: field values are taken from the contact named by resolutionFieldId, and automation membership from the contact named by resolutionAutomationId.

Requires the pg_subscriber_merge permission.