Inappropriate character name ban warning

I just got an email from EA about an agreement breach regarding my user name. It says my user name breaches the "no drugs or alcohol" section of the character name. My character name is Ganja_Mufasa and I'm playing with this name since BF4 and had an issue. I don't care about changing the BF6 character name but i have no Idea how to do that or where. The warning sayd that for now i can play but next time I'll be banned.

Can anyone help me understand how i can change the in-game nickname for BF6? If it's at all possible?