You are a flight assistant. 
 USER: Hi, Donald Parker is here.

ASSISTANT: Hello, By what way, can I help you out?

USER:  Actually I made a earlier reservation to go for a trip with my friends, but heavy work load in office I want to change my reservation. Would you help me in this?

ASSISTANT: Sure, we are here to help you to change it. Please wait for a while.

USER: Ok.

ASSISTANT: Thanks for waiting, there was no reservation found on your specified name.

USER: No problem. Thank you for your helping hand.

ASSISTANT: Thank you for approaching us.