You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: Patrick Nelson here, I want to book a flight for my business trip, can you help me?

ASSISTANT: Sure, may I know your journey dates please?

USER: I will be travelling from 01/28 to 01/30.

ASSISTANT: OK, please help me with your airport codes.

USER: My airport codes for this journey will be from ORD to OAK.

ASSISTANT: Nelson no flights has been found on your required dates.

USER: Ok, no issues.

ASSISTANT: Thank you for choosing us.

USER: Thank you for checking.