To whom should I approach to waive penalty imposed on me?
Ans : Your question is comical.
Firstly you have not stated details of charge/procedure followed.and expect a considered view to be formed on the admissibility of appeal.
Secondly there is nothing like waiver of penalty. It is not a late fee fine. The Appellate Authority has power to reduce/set aside the penalty. It also has power to remand back the case to Disciplinary Authority for fresh orders and also has power to enhance the penalty after issue of SCN if it finds that penalty is less conmensurate to misconduct.
Thirdly you have deprived yourself of the opportunity of filing appeal within 46 days.