Do we have to serve full notice period if I reign in bench

Hi I'm in bench for 60 day's and HR called me and asked to keep my resignation letter,so do I have the right to ask the notice period or notice pay for 3 months in LTI MINDTREE Or any in organisation according to labour law, please suggest

What if I want to serve the entire 90 days notice period while being on bench? Is it possible?

What is the notice period in Accenture for the people who are in bench and is it negotiable or we have to serve 90 days mandatory? Please share your thoughts