I realized I had the right store (Sayumi's PKMN Center) but I had the wrong type of Pokeball. It's a Friend Ball that I have, not a Luxury Ball. Sorry about that.
Hi! I think I remember from your Pokemon shop that you're interested in Luxury Balls. I have one in UM that I'd be happy to give you when we meet to trade for my Shiny Mimikyu. The only problem is I'm not quite sure how to give it to you. Do I just catch a Pokemon in it or can I just offer it in trade? I've never tried to trade a Poke Ball before. Thank you!