You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Shirley Hill.

ASSISTANT: How can I help you?

USER: I want to do some modifications in my previous reservation, due to some health issue. Can you please help me out?

ASSISTANT: Sure, I will help you to change your reservation. I found your reservation, can you please share me your travelling airport codes?

USER: Sure, my travelling airport codes are from PHL to ORD.

ASSISTANT: Ok, may I know your travelling dates?

USER: I would like to start my journey on 08/10 and my return will be on 08/12.

ASSISTANT: Sorry, no flights are available on your route.

USER: That's ok, I will choose any other way to reach my destination on time. Anyway thank you for your information.

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

USER: Welcome.