File > Options > General Options > Accounting Integration tab
When the American Contractor option is selected, options appear that allow you to configure your American Contractor integration.
Activity/Area/Group: These fields represent the Cost Code Structure used with American Contractor. You can choose the source for the elements by selecting them from the drop-down lists.
Field Mask: This field lets you configure the format of your Cost Code Structure.
Create a Change Order for an Estimate