You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Jacob Brown here.

ASSISTANT: How can I help 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: Please give me a moment to check your reservation status.

USER: Sure.

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

USER: Ok, no worries at all. Thank you.

ASSISTANT: Thank you for utilizing our service.