So, one of your employees are leaving the company. Your first instinct is to kick them out as fast as possible and if something goes wrong you probably will not go out of your way to fix the situation. This is a terrible idea as you will make that person less inclined to talk well about you in the future!
The employee have spent time in your company and they probably liked you when they started. Had hopes and dreams of what the time with you would be that either was not fulfilled or their dreams changed during the time with you.
Unless you already screwed up your relation with the employee by being a bad company that care more about your spreadsheets than the heroes that work for you, then you have a great opportunity when someone leave. You can both learn how to be a better company and secure an ambassador that will work for you even after they leave the company!
Leaving a company is usually done with relief if the time have been less than enjoyable or with guilt if it have been a great time. Regardless of what situation you can turn it to something good by simply being nice and support the employee. Just express that you are sorry that they are leaving and then go out of your way to make the transition as easy as possible for them.
I am not saying that you should trip all over yourself to get rid of them, but take some time to sit down with them and go over what will happen next so they feel that you are there for them. Have lunch with them and have some laughs and reminisce about good times you hopefully have together.
Ask them about the reason for moving on without trying to push the issue. Some people don't want to tell you their reasons so respect that. Most importantly if something during the transition to end the employment is causing issues for the employee, then fix it. Even if it is a cost involved and your instinct is to not spend money on someone that is leaving, take that cost because it is an investment!
On that last day of the employment have a moment together with as many as you can to say goodbye to the employee. Show that you will miss the person and give a gift that really matter. Don't give them a book (unless they really like books), but give them something that is a little expensive, but still not to much.
My favorite is an iPad mini in gold with an inscription on the back saying something like "We will miss you like crazy Name! - Company Name". It's a little pricy, but the value you get in return is worth a thousand times more. You can also add a little poster or something where everyone closest to the employee have written their names and a nice farewell message (personalized if possible).
A former employee will talk about you, that is natural as you have been in their life for a while and work is the majority of our time after all. You can dictate how that conversation will go based on how the last few weeks are with your company.
If you treat them well and go out of your way to show that they have been an important part of the company and that them leaving does not change your perception of them, then they leave with nothing but good will in their hearts.
For as long as they can remember you they will speak well of you and if they should not be happy in their new workplace chances are that they will remember you and possibly ask to come back. Having that iPad means that every time they use it that feeling will be reinforced as well and most people do use the iPad quite a bit.
There is an old saying that say that even if you have had the best vacation in your life with the best hotel, great weather and the best time of your life, all it takes is a bad experience on the flight home to ruin the experience. The last experience is what we remember most.
So if you give an employee a bad experience leaving the company, or worse screw them over so they get mad they will speak of that forever. As they know inside information about your company they will speak loudly to anyone that listen about every little detail you make look bad and sooner or later that will cost you business for sure.
So treat your employees well while they work for you so they don't want to leave and should they still want to leave, make it the best experience possible. In return you will have someone that will speak well of you and they will defend you long after they have left your company.
It's the smart, and right, move to make.