In order to reschedule your appointment with Prometric, please visit their website through this link: https://www.prometric.com/HSPA 

On this webpage you want to click on “reschedule/cancel” (it should be on the left-hand side of the page under “Actions”).

Once you’re on the next webpage, it will ask you for your confirmation number, and the first four characters of your last name.

From there, your current appointment should appear, if you want to reschedule for a different date check the little box next to your appointment date and click on “Reschedule” at the bottom. From there you should be all set to pick a new appointment.