Manually deleting keys in the Licensing Database ( C:\Windows\System32\LServer ) can corrupt the RDS Role, requiring a full re-installation.
The configuration for the licensing mode (Per User or Per Device) and the designated license server addresses are stored under: rds cal license registry key free
"It is possible to reset this grace period, but resetting the grace period is not a substitute for purchasing and installing the required Remote Desktop CALs. The following steps should not be performed on a server that is in production." Manually deleting keys in the Licensing Database (