Do you intend to transfer your ticket to another person?
Officially you're not allowed to correct/change your name after booking of a ticket.
Normally little or more mistake in names will not be a problem in train - TTE's will not object. Always be humble & talk in soft tone with TTE when requesting to consider such issues in favor of you.
Complete name change may not be accepted and in that case you'll be considered without ticket and you'll need to pay ticket-less penalty charges in full again. But you'll be allowed to keep your berth and it'll not be passed to other passengers( RAC or Wait-listed).
Remember nothing can be changed in Tatkal ticket.
For more information and discussion, please visit our Change of Ticket Details Forum.
Unofficial way to change name
CRS( Chief Reservation Clerk) do have some discretionary powers and they can change it for you. But only if you go through some channel who knows CRS( relative, Railway employee or even a VIP link). Don't forget to carry your id proof in that case.
