Trending @Accenture; DOJ offer letter query

I was offered a position by IBM with a DOJ of 23-Jan-2026 based on a 60-day notice period. However, my actual official notice period is 90 days, so I requested the DOJ to be changed to 24-Feb-2026. The hiring manager has approved this change, and I also received an email confirming the updated DOJ.

However, I have not yet received the revised offer letter reflecting the new date. What should I do now?