How to downgrade Windows 10 to Windows 8.1?

Recently I've formatted my C drive and installed Windows 10. I can't find the downgrade option after going to Settings>Update and Security>Recovery. Is there any other way I can downgrade Windows 10 to Windows 8.1?

Laptop Name: Lenovo Y50-70

Recover your windows to the day before you installed windows 10. Try Windows recovery but backup your essential data before. If this doesn't work, install a bootable windows 8.1 and then try repair.

If you formatted and installed Windows 10 clean, you can't go back. It only works if you upgrade and then keep the windows.old directory.

Formatting your 'C' drive wipes it clean, there's no going back.

The other three respondents are correct. By formatting the hard drive and installing Windows 10 clean, there's no prior operating system to go back to.
If you want to use Windows 8.1 again, you will have to do another format and full install.

I would say you should start with Lenovo support. Most newer laptops have a recovery partition that can be used to restore your laptop to its factory settings. Formatting your C: drive would not delete the information in this partition. The article below tells how to access this partition and how to order recovery media that you can use to restore Windows 8.1 to your laptop.

How can I get a Product Recovery CD or DVD? - https://support.lenovo.com/...s/ht035659

NOPE. I have a Windows 8.1 laptop, and it comes with a limited offer for free Windows 10. Part of the form: YOU Can't REVERT TO FACTORY SETTINGS AFTER THE UPGRADE.