Under the Manage License button, you can click to the deactivate button. That will clear the activation.

    Also, if the license is at maximum activations then you will be given the option to clear all activations if you try to activate another computer.

    Since your key is a 1 computer key, either way works the same. however, if your key was for multiple computer then the clear all option would clear all activations so you would have to reactivate everything. So in that case, you would maybe want to go to the Manage License button from the computer you want to deactivate and only deactivate that computer.

    I will send you an email about upgrading to a 2 computer key.