You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I would like to change an existing reservation as my plan to meet my grand parents got post pone due to my health issues. Can you help me with this?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while. May I know your name?

USER: I am Donald Wilson.

ASSISTANT: Thank you for providing your name. Please wait a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, there was no reservation found on your name.

USER: Ok, not an issues. Thank you for your information.

ASSISTANT: Thank you for choosing us.