Each Terminal Server Client gets a license the first time it connects to the Terminal Server. The Client connects with that license until the license expires. The license is stored in the Client’s registry. Thirty-two bit RDP clients store their license under the key HKEY_LOCAL_MACHINE\ Software\ Microsoft\ MSLicensing.
To clean the Client’s license cache, just delete this key (and its subkeys). The next time the client connects to the server, it will get another license. For 16-bit RDP clients, run regedit /v. Then delete the keys under “\Software\Microsoft\MSLicensing” to clean the Client’s license cache. You can also delete the BIN files from \Windows\System\Regdata