How to delete/reorder a Contact from a Webform
Sorry, the module does not have any mechanism for reordering contacts. The only solution is to reconfigure the contacts manually. Since you are wanting to add a new contact #1 and get rid of contact #2, you don't have to mess with #3 or #4 - they can stay put. Just configure #2 to have all the properties of #1, and then change #1 to be like the new contact you are wanting to add.