Sharing one sim card between two ipads?

Just picked up a 12.9 iPad Pro to go along with my 11" iPad pro. I'd rather not add another cellular line and was hoping I could just switch my sim card back and forth as needed. Everything I'm reading talks about transferring your plan to a NEW device but doesn't address if it's possible to switch back and forth whenever you want. I prefer cellular on my 11" most of the time but I'm traveling soon and want to take the 12.9" in case I need to work while gone. I'd want to switch it back to the 11" iPad after the trip. Is this possible? Thanks in advance.