Let's say your client calls you up and says they need to move the rental period for their project. You can quickly make this change on the project by first clicking 'More' on the Line Item Group and select 'Edit Names and Dates'.
Then, select the new date ranges.
After, you can select if you need to recalculate the pricing for this new rental period. This is especially useful if you price your rentals by day and the rental period is changing.
Finally, click 'Update'