How to get early release in HCL

HCL is my first company and I will resign as I got better offer. The official notice period is 90 days. But I have to get release within 30 days. Should I discuss it with my RM or with the HR directly?

My last RM left the org and with the new RM I am working only for a month and already had multiple heated conversations. He is very toxic. Please share how to deal with early release.

I am a non billable resource.