I would like to change my name in Xth/XIIth/ College certificates.

My name in Xth certificate was SHANTHI (A) RAJESWARI

I want to remove the alias and want to change as 'SHANTHI RAJESWARI'.

Please let me know the below:

1) Procedure to change
2) Hw long will it take
3) Supportive documents which needs to be submitted.

Thanks in Advance!!!