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

ASSISTANT: Hello. How can I assist you?

USER: I need to amend my reservation, can you help me out please?

ASSISTANT: Ok, sure. I will amend your reservation. Can you please wait for a while I will check and let you know.

USER: Sure, take your own time.

ASSISTANT: Sorry, no reservation found on your name to change.

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

ASSISTANT: Most welcome.