The booker_email field is now supported in PUT /reservations/{id}, allowing partners to set or update the booker’s email address on a reservation. If booker_email is omitted from the request, the existing value is retained. Sending an empty string does not clear the existing value. Unsupported characters in the email address are rejected following existing email validation rules.

Example request:

{
  "booker_email": "booker@example.com"
}