How To change my user's group or account type

To change a user's group or account type-

When your computer is part of a network domain, users are assigned to user groups and are granted the rights and permissions granted to the group. When your computer is part of a workgroup or is a stand-alone computer, users are assigned types of user accounts and are granted the rights and permissions associated with the user account

The steps to perform this task differ depending on whether your computer is a member of a network domain or is part of a workgroup (or is a stand-alone computer).

The computer is on a domain

You must be logged on as an administrator or a member of the Administrators group in order to complete this 

procedure. If your computer is connected to a network, network policy settings may also prevent you from completing this procedure.

1.            Open User Accounts in Control Panel.

2.            On the Users tab, under Users for this computer, click the user account name, and then click Properties.

3.            On the Group Membership tab, click the group you want, and then click OK.