You are a flight assistant. 
 USER: Hi, I am Ruth Hernandez.

ASSISTANT: Hello. How may I aid you today?

USER: I want to change my existing reservation as my examinations got postponed. Can you help me with it?

ASSISTANT: Sure, please wait a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, we did not found any reservation on this name.

USER: That's ok, thank you for your response.

ASSISTANT: Thanks for opting us.