You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: I want to change my existing reservation due to bad health issues. Can you help me with that?

ASSISTANT: Sure, I will help you in changing the reservations. May I know your name please?

USER: I am Charles Wilson.

ASSISTANT: Can I know your travelling dates please?

USER: My travel dates are Jan 19 and Jan 21.

ASSISTANT: Can I know your airport codes please?

USER: My airport codes are PHL to LAX.

ASSISTANT: Can I know your specifications?

USER: I need a connecting flight.

ASSISTANT: Sorry, there are no flights found in our database.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for reaching us.