You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation. Can you please help me in that?

ASSISTANT: Sure, can I have your name please?

USER: Sandra Garcia here.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no active reservation on your given name.

USER: Ok, not an issue. Thank you for checking.

ASSISTANT: Thank you for reaching us.