yes you can .. just go to survival area and in the secret club you get showed to youll see diffrent leaders in there each day
Well There is no way to rematch the gym leaders unless if you hack it!
You can't rematch them unless you start again
On eather game, sadly, you can't. But on Diamond, Pearl, Platinum, Heartgold and Soulsilver you can...
You cannot.
No unfortunately :(
Hackless, NO!
You cannot.
You can rematch all 16 gym leaders at the Fighting Dojo near the Saffron Gym, you may have a rematch against the gym leaders only when you got their Poke-gear No., while they are away from the gym at a specific time each week also the rematch is in a specific time (ex. Whitney is missing from the gym any day on 12:00-16:00, go to the Goldenrod Dept. Store 6th floor and get her number, her rematch call is on Saturday Afternoon )
america
go to serebii.com it tells how
You'd have to use cheats.
I'm sorry, my last answer was wrong, you can rematch them, but you first have to get their number, and some of them will only rematch you on certain days.