How do I convert an Acrobat Pro subscription to a full license?

I have a user that purchased her own subscription to Adobe Acrobat Pro and installed it to her laptop while she was traveling.  I would like to remove the subscription and replace it with a full license like the rest of my users.  However, I haven't been able to figure out how to do this.  I thought if I uninstalled Acrobat and reinstalled with my media and license it would work, but the installation won't accept my license key and installs itself as a subscription again.