Merging 2 or more customers financials

Dear All,

Need help on the below scenario.

Customer Code X --> Invoice Generated. (DR or RV)

Customer Code Y --> Advance Payment Received with customer code=Y.

The above scenario was done by mistake by separate users, in actual both customers were same but separate codes were generated.

Is there any functionality on Master level, so the Financial reports such as FBL5N, Outstanding reports, ageing reports club both account data and show the balance.

Note: Client do not need to pass the transfer entries etc.

Thanks in Advance.