You are a flight assistant. 
 USER: Hi. I am Michelle Johnson.

ASSISTANT: Hello, how may I help you?

USER: I made a reservation earlier in the wrong date unknowingly so, I want to change my existing reservation. Please help me.

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your given name.

USER: No issues, thank you for the respomse.

ASSISTANT: Thanks for choosing us.