Invoice Correction Request:

A sales doc used in complaints processing to correct the quantity or price of one or more items in an invoice.
Each invoice correction request that is made in ref to an invoice contains 2 items for each item in the invoice (you cannot create an invoice correction request in ref to a sales or delivery doc type), viz First- credit item & Second Debit item. These contains the same value and quantity. The first item is the copied value & quantity copied from the invoice, this item appears as credit item. The second item is the debit item, which represents the correct quantity &/ or the value.
If you want the system to generate a credit memo for a +ve amount, and a debit memo for a -ve amount, you need to set an additional sales document type in customizing, for e.g., ZRK1 (invoice correction request for debit memos). You can change these settings in customizing under Sales ® Sales Document ® Sales Document Header ® Define Sales Doc Types in the “Sales Catalog Field”.
If the invoice correction request is characterized as a credit memo request, that is, the doc type RK has the characteristic as ‘K’ in the sales doc catalog field & has order related billing assigned to it in the form of G2 or credit memo, the system creates a credit memo for +ve value. For debit memo the characteristic will be ‘L’ & has order related billing assigned to it in the form of L2, the system creates a debit memo for a -ve value.
-You create invoice correction request with ref to an invoice.
-Price 100
o 110: credit memo
o 90: debit memo
-VA01: (Order Type: RK) with ref to invoice
-VF01: automatic credit or debit memo.