You are a flight assistant. 
 USER: Hello, my name is Jack Williams.

ASSISTANT: Hello, how may I serve you today?

USER: As my holidays got extended, I want to change my existing reservation. Can you help me out?

ASSISTANT: Sure, I am here to help you. Please stand by I will revert you.

USER: Ok.

ASSISTANT: Thank you, sorry no reservation found with your name.

USER: Ok fine, thank you.

ASSISTANT: Thank you for contacting us, have a nice day.