Currently, the correct way to rename a computer is to first rename it in Lansweeper and then rename the machine itself. You can rename a computer by browsing to its Lansweeper webpage and then hitting the Edit Asset button, under Asset Options. When the machine is rescanned, its existing database entry will then simply be updated. If you don’t rename the machine in Lansweeper first, a new database entry will be generated for it.
We've been considering implementing an automatic rename procedure based on MAC address, but duplicate MACs are not an uncommon occurrence, particularly on virtual machines.