If the hotel is in the US, you can probably get away with the "second named guest" trick.

Just a little P.S.... most employees like to be "shown appreciation" with a cash bonus, not be given something they may or may not want or value. If there is further context that makes you think your employee really wants the hotel stay (a weekend away with their partner, etc.) then great. But you might just be putting your employee in an awkward position with the "check in together and I'll leave" idea. If you're trying to burn points instead of spend cash, then you can simply gift the points to your employee...