Renewed or Replacement Cards for VISA/AMEX

Hi Team, 

We have understood from VISA and AMEX that under certain conditions, the credit cards are renewed or replaced. In this regard, please advise if the new card is inserted as a new row on the Employee profile credit card information tab or it updates the existing card with the updated details. We understand that on the Installation Options, we need to select both "Include Account Maintainence" and "Update Profile for New Account" so that the new credit cards are automatically updated on the Employee Profile. 

On what basis does the Load External Data process identifies to which Employee does the credit card number belong to? If its the Employee ID, does the Employee ID also available with AMEX?