Hello.
Hello, how may I assist you today?
I need your assistance  to change my travel dates in the previous reservation. Will you help me to do that?
Sure, may I know your name?
My name is Pamela Adams.
Ok, please wait for a minute.
Ok, take your time. I will wait for your reply.
Sorry, there is no reservation found on your name.
That's not an issue for me. Anyhow thank you for your valuable time.
Thank you for reaching us.