you can go to a building in eterna city that has a man that will re name your pokemon.
he is in a building near the biking route,but not the closest one.
Chat with our AI personalities
You can rename a pokemon by going to the Name rater
Go to the namerater in Lavender Town or rename it right after you catch it.
how to get a togepi in Pokemon platinum
There is no grunt that you can give a Pokemon to in Pokemon platinum.
There is a building next to the POKeMART in Eterna City. Talk to the old man at the table in there and he'll rate your nickname and/or let you name or rename it.