There is no such thing as a "shared license" for Studio One.
There is one license per person, that other engineer should be on the same premises as you, to use one of his activations you should be working in his studio on one of his systems that he's letting you use. He must have direct access to all the systems under his control, therefore he needs to be the one to update the software. Ask him to come over to your computer to assist you.
If he's not on the same premises then you need to acquire your own Studio One License by purchasing one from our web shop to which you can then activate the license on your system to your account without having to re-install the software. Follow this tutorial to learn how to activate your installation of Studio One.
You can review our software EULA here.
