You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I'm Ryan Martin.

ASSISTANT: How may I assist you?

USER: Due to sudden change in the dates of summit which was going to be held in the place,so I want to cancel my recent reservation, can you please help me?

ASSISTANT: Sure Martin, wait a moment.

USER: Sure.

ASSISTANT: Martin there is no reservation found for you.

USER: Oh! It's ok, thank you for your quick response.

ASSISTANT: Welcome. Thank you for choosing us.