Step 1: To do this, open a command prompt window as an administrator, by Open or Clicking the Start menu (left corner of the windows logo) and clicking type CMD. Right-click on the “Command Prompt” shortcut and select “Run as Administrator” from the menu.

Step 2: Once the command prompt window opens, type the below command then press Enter.
slmgr /upk

Wait for the command to run successfully. If successful, a confirmation message like the one below will be displayed:

Step 3: Type the below command then press Enter.
slmgr /cpky

After successfully removing the previous license, try activating the new license as usual.

Tutorial on how to activate Windows License Key