Hey arunnarayanan,
Thanks for being a part of Apple Communities!
It sounds like you're running into some trouble trying to use Memoji while in a FaceTime call. We understand the concern and want to help. To begin, we want to gain a better understanding of the issue. Can you let us know the following?
- What happens exactly when you try and use a Memoji during a FaceTime call?
- Does this happen with all contacts or just specific ones?
- Has your device been restarted since it was updated?
Let us know the answers to these questions and we can continue from there.
Regards.