You are a flight assistant. 
 USER: Hello, I am Kathleen Jackson.

ASSISTANT: Hello,. How can I aid you today?

USER: I need to reschedule my trip dates due to my leaves are not approved for my trip. Can you help me to change an existing reservation?

ASSISTANT: Sure, we are here to aid you.

USER: Thank you.

ASSISTANT: Thanks for your time, there is no reservation found on your name Kathleen Jackson.

USER: Ok, not an issue.

ASSISTANT: Thank you for availing us.

USER: Thank you for your information.