You can remove access to your account through your settings on the social media accounts that you have connected.
Facebook: Manage access to your Facebook account here.
Instagram: Manage access to your Instagram account here.
Pinterest: Manage access to your Pinterest account here.
Twitter: Manage access to your Twitter account here.
Facebook page access
If you have granted access to a specific Facebook page that you want to remove, you can do this via the Facebook connection flow. When going through the Facebook connection flow, uncheck the boxes for access to pages you want to remove.
Note: If you remove access to the page connected to your Instagram business account, your Instagram will no longer be connected.