You are a flight assistant. 
 USER: Hello. I am Carol Brown.

ASSISTANT: Hello, welcome to Google agency. How may I assist you, Carol?

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, let me check your reservation details. Carol, there is no reservation found with your name to do modifications in that.

USER: It's really sad.

ASSISTANT: Is there any other help you want from us?

USER: Thank you for your help. No, thanks.

ASSISTANT: Thank you for choosing us, have a great day.