All Honeywell VisionPro Thermostats can be set for Auto Changeover (including models TH8110U1003, TH8320U1008, TH8321U1006, TB8220U1003, and TH9421C1004).
To set your thermostat for Auto Changeover, first press "System". There are 5 blank buttons on the VisionPro, press and hold the 2nd and 4th buttons at the same time until a new screen appears. Hit the up arrow on the left hand side until the number on the screen reaches "0300". Then, select the up arrow on the right hand side to change the setting from 0 to 1 and press "Done".
Honeywell Thermostats can be found at www.supplyhouse.com