You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Sandra Moore is here.

ASSISTANT: How can I assist you at this moment?

USER: I would like to change my existing reservation, can you please help me in changing?

ASSISTANT: Sure, I am here to help you with this.

USER: Thank you.

ASSISTANT: Can you please provide your name to check your reservation status?

USER: I already mentioned above.

ASSISTANT: Sandra Moore, there is no active reservation found under your name in our database.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for contacting us.