You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: Can you help me to change the reservation which I had done recently?

ASSISTANT: Sure, I can do that for you. May I know your name?

USER: Ok, please check for the name Thomas Taylor.

ASSISTANT: Thank you. Please wait for a while.

USER: Ok, I will wait for your response.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

USER: Ok, that is not a problem. Thank you for assisting me.

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