https://www.mathworks.com/matlabcentral/answers/99147-where-are-the-license-files-for-matlab-located
You need to locate the license file and replace its content. If you are using a standalone license, you might need to restart MATLAB before the new license is looked at. If you are using a network license, then you might need to signal the license daemon.
Alternately, if you are using a standalone license on a networked system, then all you should need to do is rerun the activation client, and that should load in the new license automatically; see http://www.mathworks.com/matlabcentral/answers/99457-how-do-i-activate-matlab
