Currently it is not possible to change your in-game name. After you have created your account and selected your name, it no longer can be changed by you.
If you are convinced a name change is nessecary, (e.g. containing words infrining on the Fableborne Code of Conduct or containing personal information), please contact the Customer Support Team and provide your case.
However please note that we will not be able to comply with your request outside of such cases.