Manager

Sheldon is a character of the day who appeared in Pokémon Double Trouble (EP110).

Sheldon is Luana's assistant and also her hotel manager. Ash and his friends first met him upon Luana's return to her hotel, instructing him to give the kids a deluxe suite to settle into; he readily agreed. Later, he acted as the judge between Luana and Ash's battle for the Jade Star Badge. When the gang were preparing to leave Kumquat Island, Sheldon was there to see them off, along with Luana and the hotel staff. In true manager fashion, his parting words were less parting and more indicative of their hotel service.

(Source: Bulbapedia)