As per Rules 11 of CCS (Revised Pay) Rules, 2008, employees has the option of fixing their revised scale of pay on a d or any ate later than 1.1.2006, when he elects to draw pre-revised pay until he earns his next or any subsequent increment. This option can also be exercised when the employee is placed in a higher pay scale after 1.1.2006 on account of promotion, upgradation of pay scale etc.
However, as per Rule Rule 6 of the said Rules the option has to be exercised within three months from the date of issue of Revised Pay Rules and the option once exercised is final.
Now, Government has decided that employees are permitted to revise their initial option up to 31.12.2010, if the option is more beneficial to them
For more details Download Office memorandum F.No: 7/14/2010-E.III(A) dated 05-07-2010