30 January 2012
The PAN card needs to be physically surrendered to the jurisdictional Income tax officer and requesting him to cancel the PAN with reasons. (However please not that PAN has no connection with business. Its your individual number).
Same thing applies for TAN and service tax registration also. (The original certificate needs to be surrendered along with a covering letter).
31 January 2012
Should u even furnish the same, the department official could issue a notice and require you to file the returns along with applicable interest and penalty.