You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Nancy Green.

ASSISTANT: How can I assist you now?

USER: Can you please help me to modify the travel dates in the previous ticket?

ASSISTANT: Sure, I am happy to help you with changing your reservation.

USER: Thank you.

ASSISTANT: Please wait a moment to check your reservation status.

USER: Sure, I will wait for your reply.

ASSISTANT: Sorry Nancy Green, no reservation has found under your name to change.

USER: It's ok, thank you for checking.

ASSISTANT: Thank you for choosing us, have a good day.

USER: You are welcome.