Adding "no thanks" text which closes your form

You can make your form dismiss/form close button appear to the visitor as text instead of a button.

Add a button to your form, and select "dismiss" instead of submit for the button action

Set the button’s background color to match the background by checking the transparency box at the bottom of the widget

Select a text color which contrasts with the background. Gray on white is the typical color scheme used for this presentation.