I don't think you can....
You can, but all you have to do is go to the Kanto region and find a trainer named Billy,school boy,he on route 15 beat him and he'll ask to exchange numbers click "yes" after that he'll tell you where the gym leaders hang out when they're not in respective gyms...
that's when you could battle them for rematches...
All of them have phone numbers, but there are certain ways to get them. I would try looking up "how to get all gym leader's phone numbers in heartgold" on google
he will be anwhere see him and you get his phone number when you talk to him
After you defeat her, you will automatically register her in the Pokegear.
There are a variety of things you can do. You can get Janine's phone number in the Mt. Silver entrance. You can also go to the top of Mt. Silver and battle Red.
you can go really early in the morning to get her phone number and rematch her again
You need to defeat the mahogany gym leader then prof.elm will phone you and then defeat team rocket
All of them have phone numbers, but there are certain ways to get them. I would try looking up "how to get all gym leader's phone numbers in heartgold" on google
The Fighting Dojo isn't a real Gym, but a place where you can rebattle Gym Leaders after receiving their Phone Numbers. The Leader of the Dojo is deep inside of Mt. Mortar, and if you beat him, he gives you the Pokemon Tyrogue, which evolves into either Hitmonlee, Hitmonchan, or Hitmontop.
talk to oak, he lets into mt silver. from there you can get gym leader phone numbers to get rematches, re-battle the elite 4, or climb mt silver and try to defeat red. keep in mind that red's lowest level is around 70 and he has a high 80's level pikachu, so if you try save first.
you use it on yourpokegear (the phone thing)
i dont think you can
71 or 72 phone numbers... I hear you can get Lance's, too, but... Meh. It's probably a lie.
Get the numbers of the gym leaders and call them for rematches, where they'll be available in the Fighting Dojo. A gym leader will stay in the Fighting Dojo until you rematch them, so you can have all of the gym leaders there. It can take a while to get the phone numbers and call all of them when they're available for a rematch, but it's better than fighting wild Pokemon (the highest you can fight is level 50 at Mt. Silver). In addition, you can call trainers that you have the phone numbers of for rematches during certain times of the day.
he will be anwhere see him and you get his phone number when you talk to him
After you defeat her, you will automatically register her in the Pokegear.
think its 99
You can't get everybody's phone number.If this is to battle him again,you have to beat the elite four again.