Open Finder, go to Applications and right-click on Parallels Desktop Lite. Select Move to Trash.
Alternatively, you can also hold down the app’s icon in Launchpad until all the icons start to jiggle, and then click the app’s delete button (x) to uninstall the app.
Note: Your virtual machines will not be affected by this procedure — only the Parallels Desktop application will be uninstalled. If you want to remove a virtual machine, please see KB 5029.
You can reinstall the app by viewing the App Store Purchases list and clicking the Install button for the app.