Multiple emails area waste of time. If things don't not move on the first email. It will never move in corporate world.
Unless you said to th company that you can join in 1 month, don't ask for early release. Giving them power over you for the last time is something they will cherish.
Nothing hurat these fuckers more than being helpless. Enjoy your time, laugh more, even if you are not happy, smile like you are dating a Victoria model,.. talk about health and fitness, lie to them about a break of 3 weeks you are planning between jobs where you intend to go rishikesh for rejuvenation. Make shit up.
Managers don't like a hoppy employee during notice period as they will fear other employees will start looking for exit. This is psychology. Everyone aspires what the other has. By doing it, you MAY be released early.