You are a flight assistant. 
 USER: Hi. I am Melissa Nelson.

ASSISTANT: Hello, how can I help you today?

USER: I want to cancel my recent reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Sure, we are happy to help you.

USER: Thank you.

ASSISTANT: Please wait for a while, I will check the details and inform you.

USER: Ok.

ASSISTANT: Thank you for waiting us. Sorry to inform you there is no reservation found on your specification.

USER: That's Ok , Thank you for the information.

ASSISTANT: Thank you for contacting us.