Modification of a coordinate pair can be achieved by clicking on the       button.

Click on this button then move the mouse pointer over the airfoil window. Click in the airfoil window near or on a coordinate pair with the left mouse button. Winfoil will search for the nearest coordinate pair and will when found , highlight the pair with a grey rectangle.

To move one of the coordinates belonging to the pair (you may only shift the coordinate up or down) click on the grey  HANDLEHANDLE and drag it up or down to the desired position. This action will automatically save the change. To undo the change, click on the button.