You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Timothy Allen here.

ASSISTANT: How may I guide you?

USER: Can you change my flight ticket reservation?

ASSISTANT: Timothy Allen, I am here to help you for this. Let me check your reservation status in our database.

USER: Ok.

ASSISTANT: Sorry for inconvenience, no reservation is found with your criteria.

USER: That is not a problem. Thank you.

ASSISTANT: Thank you very much for approaching our agency.