This method involves editing the Invoice directly and populating the Item Hire To fields to indicate the items are returned.

When editing an on-hire invoice, click the Show Line Details link.
Enter a specific Hired To date, this will be the date the items are returned. You will need to manually type a date/time into the Hired To date field.

AutoCalc
Depending on several factors, you may need to manually run AutoCalc after doing a partial return this way in order to calculate your new price.

This can be easily done by pressing the blue AutoCalc link above the totaling section of the invoice screen.

Partial Returns

Partial Returns