Trending @Cognizant; Early release

I got an offer today and I’ll need an early release from cognizant. I have submitted my resignation on people hcm portal and sent an email to home manager and project manager.

Currently I am at associate position and non-billable because billable project is yet to be assigned.

Please give me some tips and tricks so that I can convince my manager to provide me an early release.

If I want to buyout my notice period then also how to do it and whom to reach out ?