How to add another user as local administrator on the machine that is joined to Azure AD?

By default only the person who joined the computer to Azure AD is granted local administrator rights. To add someone else as local administrator on the machine that is joined to Azure AD, follow these steps:

1. ask the user to sign in to AAD, if they have never done it on this computer
2. sign them out and sign in with local admin account
3. run the Command Prompt as administrator and type in the following command:
   
   net localgroup Administrators UWINAD\{uwinid} /add