how to pass credit note against open invoice in ar auto

Hello All / Bharat,

how to pass credit note against open invoice in ar auto,

we have requirement, where user want to pass credit note against AR open invoice. credit note amount will be same as invoice original amount., i need your support to prepare required script or logic to get desire result.

requirement is that system should auto create credit note and apply against particular open AR invoice.

eg: there is an invoice value of 1000$, for this invoice i want to pass credit note .

now it is also possible that there is already receipt applied against that invoice, so first system should auto unapplied the receipt then pass credit note and apply.