Once this option has been enabled for a given user, the system will allow them to change the date and carrier of several orders massively from the Shipping Order Summary screen.
Go to Setup > Users > Company Users.
Use filters to "Search" for the user.
Go under the Actions column and click on "Edit".
Select the "Options" tab.
Select the option Allow changing the date and carrier of the orders massively.
Click on Save.
How does this option work?
Once this option has been enabled for a given user, they will see the Mass Update option when clicking on the Actions column from the Shipping>>Order Summary screen. Read Mass Update option from the Shipping Screen for more information.