Milestone API - Assigned By

Milestone API - Assigned By

Hi,
I am using the following API ( https://www.zoho.com/projects/help/rest-api/milestones-api.html#alink3) to create a Milestone. A mail notification is received from 'notifications= zohoprojects.com@notifications.zohoprojects.com', once a milestone is successfully created in Zoho Projects.
Problem: In every email, the default portal owner name is showed in the 'Assigned By' field. 
Question: Is there a url parameter where we can pass the 'Assigned By' user name/email?