Greenlight CM™ allows you to track that executed purchase orders are returned by vendors and subcontractors.
1.From the ribbon toolbar, click Greenlight.
2.Click Manage Greenlight, 
.
The main screen displays with the Users tab active:
3.Click the Configuration tab.
The following screen displays:
4.In the Configuration Settings grid, locate the Require Signed POs check box.
5.Click the check box to enter a checkmark and turn on the requirement.