In the KcPersonExtendedAttribuets Id field, search for and select the individual you want to validate the information for. Then click the [search] button.
The search result should display.
Even-though you won't be editing , click the edit link for that person (this is the only way to view all the info in the Extended Attributes, clicking on the KcPersonExtendedAttributes Id link will only show a portion...)
The window will open displaying all the other info that was loaded. Scroll down and you should see the appointment info (towards the bottom of the page).
Then just cancel out of that document when you are done viewing it.