Delete Record from MVG

Hello,

I need to remove some records from M:M MVG. Scenario is like that if there is any record available in the MVG having Primary as 'Y', i need to add one new record here ,need to set the primary of this new record as true,and then delete the old record.The code which i used is as follows:

    var OrgMVG = bcServiceAgreement.GetMVGBusComp("Account");
    var oAssocMVGBC = OrgMVG.GetAssocBusComp();
 
    with(oAssocMVGBC)
           {
                           ActivateField("SSA Primary Field");
                           SetViewMode(AllView);
                           ClearToQuery();
                           SetSearchSpec("Id", newAccountOrg);
                           ExecuteQuery(ForwardOnly);
                           var isExist = oAssocMVGBC.FirstRecord();
                           if (isExist)
                           {
                             oAssocMVGBC.Associate(NewAfter);
                           }              
                                                
                           
                           ClearToQuery();
                           SetSearchSpec("Id", newAccountOrg);
                           ExecuteQuery(ForwardOnly);
                           var isExist1 = oAssocMVGBC.FirstRecord();