Mojang will give Minecraft players the ability to change their name on February 4th. While it's a pretty simple process, there are some important rules to be aware of.
To change your name, do the following:
1. Go to your Mojang account page.
2. Click the “change” link next to your Minecraft name.
3. Choose your new name.
Older Minecraft accounts will need to be migrated over to Mojang before they can perform this change. You can migrate your account for free here.
Both the spelling and capitalization of your user name can be changed. Put some thought into your choice. While it's free to change your name, you'll have to wait 30 days until you can do it again.
Minecraft names are still unique so you can't choose one already in use by someone else. Even if you convince them to change their name, you can't switch to their old one right away. Their old name will become available 37 days after they switch to another.
Back in the early years of Minecraft, it was possible for players to register a username before they actually bought the game. These usernames will soon be deleted from Mojang's system, though, so paying customers can snatch them up. If you have one of those unpaid user names, here are the steps recommended by Mojang:
1. Be sure that you have access to your old, unpaid Minecraft account. You will need access to its registered email address. If you cannot access that username, you can contact customer support, provide your registered email address or physical registration location, and we will set it to a new email address.
2. If you haven't already, register a Mojang account at account.mojang.com/register. You cannot have more than one Minecraft username per Mojang account.
3. Purchase Minecraft with a gift code from minecraft.net/store or through a Minecraft prepaid card from a retail store. Old usernames can only be upgraded with gift codes or prepaid cards.
4. When redeeming your gift code or prepaid card at account.mojang.com/redeem, an option to import an old username will be available.
If you can't complete this process before these unpaid accounts are purged, you could still register the name normally. However, you run the risk of someone else grabbing your preferred name before you manage to do so.
Name changes won't wipe other parts of your account. If you're banned from a server, you'll stay banned. You'll also retain whitelist and op status on servers along with your inventory, pets and stats.