How can i uninstall parallels desktop to reinstall on other computers ?

Hello
we have bought a few licences of parallels desktop for mac.
Each year, we install all our softwares on a computer (master) and then we copy this master on the other computers (with carbon copy cloner). Last year, after the copy, we had to enter the serial number on each computer so we don't have any serial number available for a new installation.
This year, we want to clone the new master but we don't want to loose our licences of parallels. How can i uninstall parallels desktop before copying the new master on my computers ?
Sorry for my english !!!
Thanks for your answers
Pierre