In some cases, the company can offer to buyback slices from participants. When this happens individuals are paid by the company. One slice = one unit of currency depending on the currency your fund is using. When the company buys the slices the slices are removed from the pie and the model will self-adjust.
If the company uses company money to buy back an individual’s slices the slices will vanish from the money and the Pie will recalculate everyone else’s shares which means they will all have a higher percentage. When someone sells their slices back to the company they are getting a chunk of money and forgoing a share of future profits.
If another individual buys someone’s slices the slices will transfer to her and she will get the profit distributions, when and if payments are made. In other words, the slices do not vanish, they stay in the pie but belong to someone else.
Of course, more established companies may warrant a value that exceeds the Slicing Pie model value. In these cases, the fair market value should be used, not the Slicing Pie model value. Your company’s managers will determine whether they will allow one participant to sell slices to another. I personally think it’s okay (as long as it’s a legal transaction). I recommend that you avoid selling to people who are not actively involved in the company, however. This will create an absentee owner situation which isn’t great.