How do you get past the person who wont let into road that leads to sunnyshorecity in Pokemon diamond?

You're likely talking about the old man blocking the way to Sunyshore City in Pokemon Diamond. He's a bit of a roadblock, but you can get past him with a little bit of effort!

Here's how to do it:

1. Talk to him: He'll tell you he's waiting for his granddaughter to come home.

2. Go find his granddaughter: She's at the Pokémon Trainer's School, just west of the old man's position.

3. Talk to the granddaughter: She'll explain she's practicing for the upcoming contest. She needs some inspiration for her stage entrance.

4. Go talk to the old man again: He'll have changed his mind and will let you pass.

Now you can continue your journey to Sunyshore City!