Destroy Webforms [roles] array.

Hello,

I'm almost a programmer but I'm not quite there yet :). I need some help changing the value of a webform array. When using print_r to print out webform's array data I get [roles] => Array ( [0] => 3 ). I would like to set the value of this array to [roles] => Array ( ) which will make the form invisible to that role.

How would I go about setting the value of the $webform var to [roles] => Array ( )?

Thank you!

Lee