NOTE: If you are interested in creating or updating profiles in Klaviyo, you should be using the Identify API instead. The best use-case for this route is changing a profiles's email address or other primary identifier after a profile already exists in Klaviyo.
Add or update one more more attributes for a Person, based on the Klaviyo Person ID. If a property already exists, it will be updated. If a property is not set for that record, it will be created.
You can update any attribute, by sending one or more attributes along their new values, as query parameters. Recommended attributes for this endpoint: $email, $phone_number, $id