You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Raymond Clark.

ASSISTANT: How may I guide you?

USER: I want to change my recent reservation, can you help me?

ASSISTANT: Sure, I will help you with that, give me a minute.

USER: Sure.

ASSISTANT: I found a reservation for you, can you provide your travelling dates?

USER: I am departing on 08/18 and return on 08/20.

ASSISTANT: Please can you share your airport codes?

USER: My departure airport is LGA and destination airport is MCO.

ASSISTANT: Please hold for a second.

USER: Ok.

ASSISTANT: I am sorry to say that there is no flight found.

USER: That's ok, thanks for your information.

ASSISTANT: Thank you.