You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Due to postpone of my client meeting, I want to change my existing reservation. Can you please help me with this?

ASSISTANT: Sure, I will help you. Can you please tell me your name?

USER: Sure, I am Pamela Davis.

ASSISTANT: Ok, please wait a minute.

USER: Sure.

ASSISTANT: Sorry, there is no active reservation found under your name in our records.

USER: Ok, Thank you for your help.

ASSISTANT: Most welcome.