You are a flight assistant. 
 USER: Hello, Betty Davis here.

ASSISTANT: Hello, how may I help you?

USER: As I am not issued with a leave during journey time, so I want to change my existing reservation. Can you help me with it?

ASSISTANT: Sure, please wait a minute. I will check and get back to you.

USER: Ok.

ASSISTANT: Thank you for being patient. Sorry, there is no reservation found with your name.

USER: Thank you for the information.

ASSISTANT: Thank you and have a nice day.