nohb's post in Move notes from personal to business was marked as the answer
At this time moving notes between personal and business notebooks is only available on the desktop and mobile versions of Evernote. I've moved this over to Product Feedback so that you can vote on this for future versions of Evernote Web.
nohb's post in How to make a notebook in Evernote local - that will not sync was marked as the answer
While you can't change the synced notebook to a local one, you can create a new local notebook then move those notes to the local notebook.
To create a Local notebook: Click File > New Notebook > New Local Notebook
To move multiple notes to a new notebook, select all the notes (shift+click) then on the right side you will see a button that says 'Move to notebook'.