Any users who have authenticated will not have their sessions dropped during the license replacement procedure will not have their sessions dropped.

The license replacement process takes less than a minute.  Any users who attempt to authenticate in the time between when the trial license has been uninstalled and the production license has not yet been installed will fail authentication.

Uninstall the trial license

1. From the Security Console select Status> License > Setup.
2. Click on View installed licenses.
3. Left click the license ID and choose Uninstall.
4. Check the Yes, uninstall license box.
5. Click on the Uninstall License button.

Do not restart the server!  Install the new license right away.

Install the production license

1. From the Security Console go to Setup > License > Add New.
2. Browse to the folder containing your license and select the license file (it ends in .xml).
3. Click Next.
4. Verify the information regarding your license is correct.
5. Click the Install button.