You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I am Dorothy Harris. Due to some slight changes in my busy schedule, I want to update my existing reservation to some other dates. Will you please help me with that?

ASSISTANT: Sorry, there is no reservation found.

USER: Oh! may be some thing went wrong while I was doing my reservation. Anyways, thank you for searching.

ASSISTANT: Thank you.