You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I want to change my reservation, can you help me with that?

ASSISTANT: Sure, I am happy to help you. May I know your name?

USER: Sure, Samantha Mitchell here.

ASSISTANT: Thank you. Please wait for a while, let me check your reservation status in our database.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry, I did not find any reservation under your name in our database.

USER: Ok, thank you.

ASSISTANT: You are welcome and thank you for choosing us.