I will be traveling from LHR to Miami and then 4 hours later to Rio de Janeiro, it is all one ticket. I want to check a bag in, but with a few presents for my friend in Miami. Will I be able to take my checked in bag out and remove the things that are for her? Will the baggage tag be the same all the way through to GIG or will they issue a new baggage tag in MIA? And will I be ok to go out of the airport and then get back in?