tSwitch is a free wordpress plugin and it allows theme developers to switch theme from anywhere within a wordpress installation.
The switch doesn’t affect the theme shown to non-administrator users.
The root menu item displays the name of the currently active theme.
Children themes are displayed as submenu items of their own parents.
The plugin can be temporarily disabled with one click, without the need to completely deactivate it.
To install tSwitch
Login to wordpress (wp-admin).
In your admin dashboard click plugins and select Add New.
Type tSwitch in the search field and click Search Plugins button.
After the successfully Installation click the activate Plugin link to activate the plugin.
Download tSwitch wordpress plugin. Download link
Unzip and upload it to your WordPress wp-content/plugins directory.
Login to wp-admin. In your admin dashboard click plugins and activate the tSwitch wordpress plugin