You cant open the door.unless you have the Members pass which allows you to get Darkrai. and you can gat the pass only by a wifi event. hope this helps :)
Chat with our AI personalities
You have to get the member card event.
he is in canalave city
The sixth gym is in Canalave City of Pokemon Pearl, west of Jubilife City.
He's in the house that's on the left just before the Pokemon center in Canalave city
Canalave City, go to the house above the Pokemart & yes, he does delete HM moves!