Depends on the key. Some of the transponder RFID chips are molded right into the plastic and therefore are sealed. Some of the older ford transpoders are inserted into the key head and and cover snapped into place. Sometimes these would fall causing even more problems.
Now heed the following advice. For I am a locksmith and I know what I am talking about.
Depending on the make of the vehicle you may be able to get just a mechanical key for the door. Leave the exspensive to copy and even more exspensive option of having la ocksmith come out, make the key and then program it into said vehicle, inside the vehicle. Your mechanical key will get you in. Even less expensive to have someone come out and unlock your car to get the working key than to make one from scratch.
There are only a handful of cars that are "dealer only" to copy keys or make replacement keys when they are lost. A good automotive locksmith will be able to tell you whether your vehicle falls into that catagory.
Dont wait hours for your roadside service company to send some one out for lost keys, lock outs, flat tires etc. Call who ever you want and then submit the invoice to said service company for reimbursement up to your coverage limit.