You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER:  I am Brian Nelson made a earlier reservation to go for a trip with my friends, but heavy work load in office I want to change my reservation. Can you help me in changing?

ASSISTANT: Sure, I can help you with that. Please wait for a while.

USER: Ok.

ASSISTANT: Brian, there is no reservation found under your name to do modifications in that.

USER:  Ok, not an issue. Thank you for availing me.

ASSISTANT: Thank you for reaching us.