Examples of conversations about gratitude

At the Booking Counter
Robert: Two tickets to Las Vegas, Please.Osman: Business class or executive class?Robert: Executive class. How much is the fare?Osman: 60 dollars, sir.Robert: (Giving the money = 100 dollars)Osman: Here are your tickets.Robert: Thank you. What time does the train leave?Osman: At 11.20 am.Robert: Thank you. (Moves away)Osman: Excuse me. Just a moment, please.Robert: Yes, what is it?Osman: Here’s the change. You didn’t take it.Robert: Oh, I forgot. You’re so kind. Thank you so much.Osman: Not at all.