You have less than 30 days to change your mind.

[davidhk129]

If you find Windows 10 not your cup of tea, you have less than 30 days to revert back to Win 7 or Win 8.1.

Start button > Settings > Update & Security > Recovery .........

 

[Seth]

lol unless you created a system image before the update like I did

 

[BigFeet]

Or just reinstall 8.1

 

[jelabarre59]

Or you do what I did for my brother's MSWin7 machine, just to make sure he had the free license available. I cloned his hard disk, used the *clone* disk to migrate it to MSWin10, made note of his new MS License number, then put the original disk back in his machine.