A:Answer Yes, but it is not necessary to switch to Windows 10 Pro for a full reset.
If the device was bought with Windows 10 Home, the license is built in the mainboard of the machine. So, as soon as you have the new disk and downloaded the install sources from Microsoft, you can run the setup and the machine itself will add the product code required for the activation.
For the reset: if you can still open the settings app go 'Update & security > Recovery > Reset this PC' it has the option to remove all your changes. Once it is done it starts with fresh out-of-box experience as a newly bought machine.