You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Catherine King. I want to change my reservation, due to some health issue. Can you please help me out?

ASSISTANT: Sure, I will help you to change your reservation.

USER: Thank you.

ASSISTANT: I found your reservation. Please provide me your travelling dates.

USER: Happy to hear that, my travelling dates are Sept 30 and Oct 02.

ASSISTANT: Ok, may I know your travelling airport codes?

USER: My travelling airport codes are IAH to LAX.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, no flights are available on your particular travel dates.

USER: That's ok, thank you for checking.

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