keyless entry programming

my sister in law lost her remote bought new one but doesnt have instructions on how to program it...
have read that you must have at least 1 workin remote
but im sure there is a way to by pass and program without ANY WORKING REMOTE at hand

can anyone help me solve problem
have searched ebay all say same must have 1 working remote but dont have 1

if you do not have a current WORKING remote to match another one too...you HAVE to go to the dealer, since you will need a scan tool for programming.