Hi @ronan.o.ciosoig,
Sign in on bitrise.io using the github login - you’ll be signed into the account that github account is connected to right now.
From there you can either delete that account, or disconnect the github account from it so that you can connect it to another account (see Change connected GitHub accounts for notes on how you can turn off an account’s github connection, or to change it to another account).
If you’d have any questions just let us know! 