You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you at this moment?

USER: Can you help me to change my reservation?

ASSISTANT: Sure, I am here to help you with this.

USER: Thank you.

ASSISTANT: Can you please provide your name to check your reservation status?

USER: I am Daniel Johnson.

ASSISTANT: Daniel Johnson, there is no active reservation found under your name in our database.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for contacting us.