Undercover tourist ticket question, adding days

[maxsmom]

Does anyone know if I buy a 2 day ticket w/ a free day if I can add on another day to the ticket if we decided we need a 4th day. If so how much would it cost? Thanks

 

[damo]

Yup, no problem. It will be difference between gate price for your ticket and gate price for your upgraded ticket. For most people, it seems to be around $10.