This is going to based on the job you are working for, so for instance, if you are working for a doctors office (or you are an on call doctor) you would want to make sure that you leave an emergency contact number for the people calling.
Other jobs it would always be good to leave an alternate number to contact someone when you are out of the office, or just to reach someone to get information or finalize a deal.
You will always want to make sure you leave your name.
Hello, you have reached _____. I am unfortunately not able to come to the phone right now, or I am currently out of the office. Please feel free to contact me via email at
[email protected]__.com or at this number if it is an emergency ___-___-____. I will be sure to give you a call back as soon as possible.
Thank you for calling.
I would recommend writing it down so you know what you are going to say. Practice it some, and smile when you are saying it so you have that pleasant tone.<span />