Can termination letter be withdrawn by employer once signed by employee?

I have the below issue.
I have resigned on 25th of January and given my notice period is 3 months I have requested for that to be shortened requesting 21st of March as end date.
My manager is mislead because HR system shows 4 weeks notice and accepts 21.03 as end date.
Also I receive termination letter saying my end date is 21.03.
However my manager realises that 4 weeks notice information was wrong and now suggests to me end date to be 31st of March.
Can HR on the basis of that withdraw resignation letter signed by me already and submit a new one with end date 31.03

In a good gesture, you should go with the new letter for a smooth exit as because you are still in job. In other case one should not accept or endorse the new letter, if already relived from the services.

Hello Prabhat,
Thanks for your reply, the question is not around good gesture but more about the legal side of things, is a termination letter legally binding or it can be changed without employees consent

@Vaselin
as mentioned earlier that notice period is 3 months, and you have requested to reduce/shorten it
now the 21 march and 31 march is just a fraction of days, and it may has taken place by discussion with upper management, above HR
However, the employee can go to challenge the change, but in that case the reduction of notice period may get lapsed, with some adverse effects on release,
so our advice is to go smooth and take release on new stipulated date.