Don't worry! If you already have a reservation, when you arrive at your National location, just go to the National counter when you pick up the rental. A National representative will be more than happy to add your loyalty number to your rental agreement. If you would like to skip the counter, you will need to cancel and rebook your reservation. Make sure you have logged into your Emerald Club account first. By rebooking your reservation, you will ensure that your new reservation has all the benefits associated with your Emerald Club account. Please note: To guarantee your Emerald Club Number is included in your reservation, you must log-in to your Emerald Club Account on nationalcar.com before booking your reservation. If you are logged in, your number is automatically attached to the reservation. How do I add my Emerald Club Member number to an existing reservation?