The automated option:
We have a feature on the web app at the moment https://seriousmd.com/doctor/doctordashboard/#/Settings
Click Manage Patients
Click Move Patient queue Event
Select the patient and pick the clinic/date of the visit and select where you want to move the appointment
Not yet available in the app but you can do it in the web browser of the device you're using.
The manual option:
Tap the patient in the queue, tap "Remove appointment" the appointment for the patient
Queue the patient on the other clinic
Go to the Notes tab of the patient. Edit the note. You'll have the ability to change the date and clinic at the top portion of the note editor.