Generally one should submit his/her resignation letter before 1 month’s notice ( If you fail to submit it before 1 month, the Authority may not pay you the last month’s salary). Don’t forget to take a receipt of it. If you have the receipt, you won’t face any problem in future. If the authority refuses to accept your resignation or to give you the receipt copy, you may send the resignation through Registered Post. Remember, in any circumstances, the authority cannot restrain you to join a higher post, provided you have any obligation or outstanding loan to the office. Thank you.