You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I be of your help?

USER: My name is Daniel Johnson. I would like to change my existing reservation, As my boss cancelled my leave dates.

ASSISTANT: Ok.

USER: Can you please, Help me?

ASSISTANT: Sure, please wait a while. I will check and get back to you.

USER: OK.

ASSISTANT: Thanks for waiting. Unfortunately there is no reservation found by your name.

USER: It's OK. Thank you, For helping me.

ASSISTANT: Thank you and have a nice day.