Help revert Use BIOVIA self-signed certificate (Default) from certificate from a recognized signing authority

Hi Folks I made a mistake by selecting and saving certificate from a recognized signing authority ( I use a incorrect ssa cert, key pair) . I need to revert back to using  the default Use BIOVIA self-signed certificate. Please advise how to do it.

Subhas.Chakravorty@kinnate.com ( 1-215 900 0116) Thanks a bunch