You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: I need to change my existing reservation as my plan to meet my brother got postponed.

ASSISTANT: Sure, can I have your name to proceed further?

USER: My name is Kathleen Martin.

ASSISTANT: Ok, please wait fo a while, let me check your reservation and get back to  you.

USER: Sure.

ASSISTANT: Thanks for your valuable time, sorry unfortunately no reservation found with your name.

USER: Thank you for your response.

ASSISTANT: Thanks for your interest, have a great day ahead.