You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: My name is Cynthia Hernandez, I want to change my reservation as my plan to visit my uncle's house is postponed. Can you change my reservation?

ASSISTANT: Sure, I am here to help you. We found new reservation on your name, please help me with your new journey details.

USER: Sure.

ASSISTANT: May I know your airport codes please?

USER: My source airport is CA-SFO and destination airport is TX-IAH.

ASSISTANT: May I know your journey dates please?

USER: I will fly on 06/01 and return on 06/03.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thanks for waiting. Sorry, there are no flights found with your specifications.

USER: Ok, thank you for the information.

ASSISTANT: Thank you for reaching us.