You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, travelling agency here, may I help you?

USER:  I want to do some changes in my reservation, as my friends are coming near me on those dates, can you please change my existing reservation? Please, check the details on Donna Thomas.

ASSISTANT: Sure Donna, please allow me a moment. Thank you for waiting. As per your credentials, no reservation found in our database.

USER: Ok.

ASSISTANT: Do you need any other help?

USER: That's ok, no issues. No thanks, thank you for your help.

ASSISTANT: Thank you for connecting with us, have a great day.