Officially the mini ones are non removable and you aren't supposed to be able to take them out and put them in another car.
They sell one for 20 that is meant for that
I personally have moved it.
Instead of using their sticky film I tape it with scotch tape.
Also, I happened to have just lost mine and didn't bother buying one for a while. When I got the new one, I added my license plate to the new transponder and put in starting from the day I lost the old one.
It retroactively found my old charges and took off the extra charge, and I was able to pay right then and there.