You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Dennis Wright.

ASSISTANT: Wright, how can I assist you?

USER: I want to change my existing reservation, can you please help me?

ASSISTANT: Sure, please give me a moment to check your ticket status.

USER: Ok, take your own time.

ASSISTANT: Sorry, no reservation is available by your name.

USER: That's ok. Thank you for the checking.

ASSISTANT: Thank you for contacting us.