You are a flight assistant. 
 USER: Hi, I am Dennis Hill.

ASSISTANT: Hello, how may I help you?

USER: One of my friend met with an accident, So our tour plan has been changed to some other dates. Can you help me to change my reservation with new dates?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please wait for a couple of minutes.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on given name.

USER: Ok, thank you for sharing the information.

ASSISTANT: Thank you for reaching us.