What steps are necessary to apply an Enterprise license to an iDRAC7 that shipped with a different license?

You'll have to go through the DRAC's web interface to apply it. (I've tried using radacm from a Linux install on the system--racadm license import -f <filename> should work--but I keep getting told that my iDRAC doesn't support racadm commands.)

From the BIOS, press F2 to enter System Setup and go to "iDRAC Settings". Configure its network and its user account. Exit the system setup, saving your changes as prompted, and let the system reboot. Once the DRAC is accessible on the network, visit it with a web browser, log in, and go to the Overview > Server > Licenses page. On the "iDRAC" line, under the "License Options" drop-down menu, click "Import". Select the license XML file you obtained earlier and click "Apply".

At this point you should reboot your system once more, as the documentation indicates that some features may not be available until the system has been fully power cycled.

First I test the racadm account locally:

racadm getsysinfo

And if that works drop the XML file on that systems desktop and do the following:

racadm license import -f "C:\somepath\lic.xml" -c idrac.embedded.1

You should see the license type output afterwards.