Duplicate Rebate condition types in Billing document

Hi All,

There is a duplicate rebate condition types updated(ZROC and ZROC). In one condition type rebate agreement updated and in another conditon type the rebate agreement number is not updated. So we need to delete one condition type where the rebate agreement is not updated. So i have searched the forum but i didn't get any program to delete the duplicate rebate condition type in billing document. So can you please help me any one how to delete the duplicate rebate condition type.

Even i have provided the workaround to user, cancle the invoice and recrate it once again, but the issue was exist with more than 1000 billing documents, and there are not able to use this workaround.

Thanks,