Comments on Profile Post by _dontlookdown_

You can make an "Other Support" ticket and have it changed. You cannot change yourself. https://grandtheftmc.net/support

If you want to change your Minecraft username, go to https://account.mojang.com/login, log in with your Minecraft email and password, and you will be redirected to the Minecraft account homepage.

Click on the button that says Change next to your Minecraft username under Minecraft: Java Edition. There you will be able to change your Minecraft username to any available username you desire. Remember, you can only change your username once every 2 weeks.

I think he means on the forums