Admitting false allegation of impotency outside court - Seeking MCD

My friend’s wife filed OP that my friend is impotent and sought declaration of marriage as NULL and VOID since marriage was not consummated during their stay together for only a week. Subsequently she never joined him at matrimonial home. My friend countered her allegation in his IA and requested the court to order for his potency test to prove that he is fit for marital life. Court has admitted his IA and ordered for medical examination. Now she approached my friend outside the court and requested for filing MCD. My friend asked her to withdraw the false allegation of impotency first. Kindly advise whether existing OP can be converted to MCD with withdrawal of allegations by her OR a fresh Petition is to be filed for MCD after withdrawal of this OP, [OR] she has to file an amendment Petition to this OP. Also, what are the steps to be followed and caution to be exercised by my friend in agreeing to her request at this stage [after 2 years of solemnization of Marriage].