I dont think they can, not that I know the exact dynamics of how they work really. :/ When you get one fitted you're given a plastic card, like a bank card type thing, with the batch number of your implant on it and the date of when it's to be removed so you can call up to make an appointment before hand. I had mine changed a month before it was due to expire and took Steve along with me to let him watch my arm being cut open. Well, being on the implant benefits both me
and him
