Duplicate Record in the list if(Trigger.isBefore){ if(Trigger.isUpdate){ for(Demand_List__c dl: Trigger.new){

trigger Updaterocord on ABC (after update,before update){

if(Trigger.isBefore){    
        if(Trigger.isUpdate){
            for(ABC  dl: Trigger.new){

if(Trigger.isAfter)
     {    
        if(Trigger.isUpdate){
            Set<String> leanAccNo = new Set<String>();
            Map<String,Decimal> loanAccNoEmicountMap = new Map<String,Decimal>();
            for( Demand_List__c dl: Trigger.new){
                if(dl.External_DL_ID__c != null && dl.External_DL_ID__c != ''){
                    loanAccNoEmicountMap.put(dl.External_DL_ID__c,dl.EMI_Count__c);
                    leanAccNo.add(dl.External_DL_ID__c);
                }
            }
           
            for(Client_Repayment_History__c obj : [select Loan_Account_No__c,Total_no_of_Meetings_conducted__c,Total_no_of_Meetings_attended__c from Client_Repayment_History__c where Loan_Account_No__c in :leanAccNo]){
                LoanAccountMap.put(obj.Loan_Account_No__c,obj.Id);
                updateRpHistObjList.add(obj);
               
            }
            for( Demand_List__c dl: Trigger.new){
                // Inital Status: Not Collected Final Status: Full Collection/ Partial Collection/Excess Collection
                if(dl.RecordTypeId == SBLoanDLRecordTypeId &&(dl.Product_Code_Formula__c ==Productcodefor814 || dl.Product_Code_Formula__c ==Productcodefor815 || dl.Product_Code_Formula__c == Productcodefor819 || dl.Product_Code_Formula__c ==Productcodefor802 || dl.Product_Code_Formula__c ==Productcodefor875 || dl.Product_Code_Formula__c ==Productcodefor876 ) && (dl.Collection_Status__c != Trigger.oldMap.get(dl.Id).Collection_Status__c && Trigger.oldMap.get(dl.Id).Collection_Status__c == notCollectedStatus  && (dl.Collection_Status__c == CollectedStatus || dl.Collection_Status__c == excessCollectedStatus   || dl.Collection_Status__c == partialCollectedStatus   )) &&  (dl.SMC_customer_attendance__c != null) ){
                 //EMI Count =1
                    if(dl.EMI_Count__c == 1){
                        //insert Client_Repayment_History__c
                        Client_Repayment_History__c rphistObj = new Client_Repayment_History__c();
                        rphistObj.Loan_Account_No__c = dl.External_DL_ID__c;  
                        rphistObj.Loans__c = dl.Loans__c;                      
                        rphistObj.Client_Name__c = dl.Clients__c;
                        rphistObj.Total_no_of_Meetings_conducted__c = 1;
                        if(LoanAccountMap.containsKey(dl.External_DL_ID__c)){
                            rphistObj.Id = LoanAccountMap.get(dl.External_DL_ID__c);
                        }
                        if( dl.SMC_customer_attendance__c == 'Yes'){
                            rphistObj.Total_no_of_Meetings_attended__c =1;
                        }else if( dl.SMC_customer_attendance__c == 'No'){
                            rphistObj.Total_no_of_Meetings_attended__c =0;                          
                            upsertRpHistObjList.add(rphistObj);
                        }
                    }
                    else{
                        loanAcctNoMap.put(dl.External_DL_ID__c,dl.SMC_customer_attendance__c);                
                    }
                }
                if(dl.RecordTypeId == SBLoanDLRecordTypeId && (dl.Collection_Status__c == CollectedStatus || dl.Collection_Status__c == CollectedStatus) && dl.PAR_Bucket__c != null && dl.Clients__c != null && dl.SMS_Partial_Collected_Flag__c == false &&dl.Clients__r.Zone__c !='Duplicate' && dl.Clients__r.Zone__c !='Invalid' && dl.OD_Amt__c != null){
                    odset.add(dl.Clients__c);
                }              
            } // End of for loop
            System.debug('loanAcctNoMap===>'+loanAcctNoMap);
     if(!loanAcctNoMap.isEmpty()){
        //updateRpHistObjList = [select Loan_Account_No__c,Total_no_of_Meetings_conducted__c,Total_no_of_Meetings_attended__c from Client_Repayment_History__c where Loan_Account_No__c in :loanAcctNoMap.keySet()];
        for(Client_Repayment_History__c rphistObj : updateRpHistObjList){
            if(!loanAccNoEmicountMap.isempty() && loanAccNoEmicountMap.containsKey(rphistObj.Loan_Account_No__c) && loanAccNoEmicountMap.get(rphistObj.Loan_Account_No__c) != 1){
                rphistObj.Total_no_of_Meetings_conducted__c += 1;
                if(loanAcctNoMap.get(rphistObj.Loan_Account_No__c) == 'Yes')
                 rphistObj.Total_no_of_Meetings_attended__c += 1;  
                 upsertRpHistObjList.add(rphistObj);
            }
        }
     }    
      if(!upsertRpHistObjList.isEmpty()){
        system.debug('@@@@ Upsert Repayment History');
        upsert upsertRpHistObjList ;
     }
        }// End of isUpdate
     } // End of isAfter
}
}
}

Refrer map loanAccNoEmicountMap in above trigger