You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER:  I want to do some changes in the existing reservation because my friends are not able to come on the those dates. Can you please help me?

ASSISTANT: Sure, I will help you. Can I have your name for checking the reservation?

USER: Sure, my name is Janet Gonzalez.

ASSISTANT: Sorry to inform you, there is no reservation found with your name.

USER: Oh, it's ok no problem. Thank you for your information.

ASSISTANT: You are welcome. Thank you for reaching us.