Before how many days did someone withdraw their resignation in TCS , anyone have any idea ?

At the time of resignation I had an offer letter but later they cancelled it and in the middle of NP every one wants an immediate joiner..WHICH TCS can't negotiate...still some companies confirmed about selection but did not give an offer in my hand.

Wait for you for at least last month, if you are confident that it will proceed. Other wise take a risk. Your yoe