Hi
you can do something like this in your functions.php (you might need to adjust a couple of bits depending on your exact scenario, but it should get you going)
add_action('wp_footer', 'wppizza_required_onpickup',null,null);
function wppizza_required_onpickup($field='ccustom6'){/*set ccustom6 to whatever field needs to be toggled*/
$isSelfPickup=!empty($_SESSION['wppizza']['selfPickup']) ? 1: 0;
echo"<script type='text/javascript'>
/* <![CDATA[ */
jQuery(document).ready(function($){
var wppizzaCfId = $('#".$field."');
var wppizzaCfLbl = $('label[for=\"".$field."\"]');
var wppizzaIsPickup = ".$isSelfPickup.";
if(wppizzaCfId.length>0 && wppizzaIsPickup==1){
wppizzaCfId.prop('required', false);
wppizzaCfLbl.prop('class','wppizza-order-label');
}
});
/* ]]> */
</script>";
}