I have a field required based on a choice in a choice field.  That works fine

contains(sForm].]Booking type],"Demo")

But when I want to have the same field required when it is either  the booking type
"Trial" or "Demo", I get stuck.  Any suggestions on how to make a field required when  either  "Option1" or "Option 2"  is selected from a choice field? .  There are 4 other choices when the fields should not be required.