You don't need to explain everything again.
They will ask if everything is the same and if you have any questions.
On the back of the card there is a square with a black and white pattern in it. That is a QR code and when they read it in Guest a Relations, it is a link to your file that is stored on their computer.
They can quickly update the card, add a new date and print a new card. It is very quick.
If you don't have your old DAS, you will probably have to go thru the process again. Some people had posted that without the old card, their file could not be located and they had to start all over.