That's not supported inherently.
If you want to do it anyway, you would need to
1. change template.
<p><b>Shipping Address:</b><input type='text' value ="<#=ShipAddress#>" /></p>
2. Place a save button in the template or somewhere else.
3. call updateRow() manually upon click of save button.
$(this).closest( '.pq-grid' ).pqGrid( 'updateRow', params );