How can I go back in HL7 patient lookup if there are multiple names to choose from to see each patient?

You can use the following steps to select a different patient on the screen. We admitted three Patients with the same name - John Doe: 
 
1. Navigate to Pre-Registration or Rapid Registration Entry tab
2. Under Host Info section, selected category as Patient.
3. Entered 'First Name' and 'Last Name' as 'John' and 'Doe' respectively. Intellihint shows up having 3 records.
4. Selected one record. 
5. Now, if you want to select some other patient, just remove single letter from the last name (removed 'e' from 'Doe')
6. Typed 'e' again in the last name and the list to select the patient will show up again

Also, you may even click on 'More Information' button in step 4 instead of directly selecting through 'intellihint' list.  This video shows the above scenario in action