You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, may I know how best I can help you today?

USER: My name is Sandra Lopez. Owing to emergency, I need to change my existing reservation. Please help me with that.

ASSISTANT: Sure, Please wait.

USER: Sure.

ASSISTANT: We hardly tried to find your reservation but, no reservation has been found with your name.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us.