You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I would like to change my existing reservation, which is done recently. Can you please help me out?

ASSISTANT: Sure, let me know your name to check you reservation details.

USER: Thank you for considering my request. My name is Gregory Lopez.

ASSISTANT: Thank you. Please wait for a while, let me check your reservation status.

USER: Sure, I will wait for your response.

ASSISTANT: I am very sorry to inform you that there is no reservation found under your name in our database.

USER: Not an issue, anyway thank you for the information.

ASSISTANT: Thank you for reaching us.