Legally there are very few restrictions... you set aq price, they agree to it, they pay, you transfer the name to them through your registrar. The transfer, if all goes well, can take up to a week or so. So it is important to realize it may take a little time and a bit of trust depending on how the exchange of money is going to happen. Money changed hands before transfer, risk is on the buyer and they may get antsy. Money changes hands after the transfer, risk is on the seller. If the amount is significant, doing 50% at the initiation of the transfer and the other 50% changes hands once the transfer is complete. Then the risk is essentially even.