By default, our read receipt is generated by the admin who created the API Token. If you would like to change it to another user in your ZD instance please provide us the email address of the user you would like to the read receipt to come from. If you would like a completely custom read receipt (e.g. email@example.com)and do not want to pay for an additional agent just create & verify a new 'customer' with the email address you want to be the author of the read receipt and email it to support.
NOTE: This is only available for paid ZD plans.