If Employee refuses to change his/her inappropriate behavior , what to do ?

The HR policies are clear

show cause

1st warning in span of six months if he did not change,

2nd warning - six months

3rd warning - disciplinary committee to deliberate of the matter and recommend way forward.

Recommendation: Termination

1. Written warning.

2. Disciplinary action as per HR policy.

Give a written warning with consequences clearly written for if it happens again. Make them sign it so they know what is going on.