You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you today?

USER: Actually, I want to change my reservation which is done recently due to some problems, can you please help me?

ASSISTANT: Sure, I will help you with that. Let me know your name to check your reservation?

USER: Sure, my name is Benjamin Mitchell.

ASSISTANT: Ok, please wait a moment.

USER: Ok, I will wait.

ASSISTANT: Thank you for waiting. I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: That's fine. Anyways, thank you for your service.

ASSISTANT: Thank you for choosing us.