You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How can I render you today?

USER:  I am David Davis want to cancel my reservation owing an emergency. Can you help me in cancelling?

ASSISTANT: Sure, we are here to aid you. Give me a minute, I will check your in name in reservation list and back to you.

USER: Ok.

ASSISTANT: Thanks for your time, there is no reservation found on your name David Davis in our database.

USER: Thank you for your help.

ASSISTANT: Thank you for availing us.