You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,how may I help you?

USER: Can you help me to change my existing reservation?

ASSISTANT: Sure, may I know your good name please for proceeding?

USER: Yes, my name is Jessica Garcia.

ASSISTANT: Sorry Jessica , there is no reservation found as per your request.

USER: Ok, thank you.

ASSISTANT: Is there any other thing that I can help?

USER: No, thank you.

ASSISTANT: OK, thank you for reaching us.