I petition for my parents immigrant visa. They both had their interview in January 2024 and some documents were missing for both. My mother provided the documents so she was able to get her visa while my father changed his mind while it was under administrative processing and decided not to immigrate. So we sent a notorized withdrawal letter. The embassy acknowledged receipt and send now they will return it to uscis. This was in 05/2024. Is there a notification once the application is officially revoked. Should I have a sent a message directly to uscis? What is the timeline for them to complete the process ?