After creating your array by selecting Draw Array:

Click on the    icon to Enter Edit Mode.

When selected the panels will appear outlined in red:

Select the panels you would like to remove by clicking on each panel one by one. The selected panels will be a solid red color instead of black. To deselect a panel, simply click on it again. 

When you have selected all the panels to remove, click the green UPDATE button.

The system information will update, and the array will be shown with panels removed. You can repeat the process to delete additional panels if desired. When you are satisfied with the array, click the to Exit Edit Mode.

Congratulations! You have successfully deleted panels after creating an array!