Staff members can simply use the returns-portal as well. It is three clicks and then the return is in the system. To make it easier for staff you can directly start a return with an order-number and email in the link, to set this up see the following integration guide.
If you have set a return timeframe and your staff return exceeds this timeframe you need to manually exend the timeframe for the return and then reset it.
Return-Settings / General / Return-Timeframe in Days
Change the number of days
Click save at the bottom of the page
Note: If you use the Advanced Rules to set up return timeframes, you generally do not need to make changes to the rules itself. The settings above set the overall return timeframe.