You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Charles Miller here.

ASSISTANT: Miller, how may I render you?

USER: I want to cancel my reservation, which is done recently. Can you please help me out?

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: Not a big problem, anyway, thank you for the information.

ASSISTANT: Thank you for contacting us.