Here’s how to disconnect a Jetpack site from WordPress.com.
Note that if your Jetpack site is still live, you need to go to the self-hosted site’s Dashboard and disconnect Jetpack from there.
Go to https://wordpress.com/sites to view all your sites.
Find the site you want to remove then click the Gear icon (on the upper right side of the box) then click “Select this site” on the drop-down menu.
On the left menu, click Settings.
It will come up with a screen that says “Jetpack Monitor”.
Under Actively Monitoring, check the box that says, “Turn Jetpack Monitor on or off. If inactive, it will be disabled for all users.”
That’s it! Your Jetpack site should be disconnected.
If the interface is not allowing you to disconnect your Jetpack site and your site is still live, you need to go to the self-hosted site’s Dashboard and disconnect Jetpack from there.
You can also try the instructions for disconnecting Jetpack sites here: