You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How may I be your helping hand?

USER: I'm Justin Young. Due to health issue, I want to postpone my trip to some other dates. Will you please help me with that?

ASSISTANT: Sure.

USER: Thank you, please check it.

ASSISTANT: Thanks for waiting, unfortunately no flight is reserved for you earlier to change. Thank You for availing us.

USER: Thank you.