Ideas to convince HR for early release

I’ve an offer letter and I want to join that. I’ve resigned and 75 days still left for notice period. But I need early release to join next organisation, my manager is ready to release in next 2 days. How should I convince HR for early release? Should tell HR about my offer letter or should I give any other reason (if yes then pls suggest some possible and practically proven reasons). My present organisation is TCS.

Pls help this is urgent.

#tcs