Hi Michael

You need to be in the page layout tab.  If I was changing from a 3 part column to a single column layout the first thing I would do is move any of the includelets (they're like building blocks for the page) that I wanted to keep (just drag them) to the top section of the page layout so there are no includelets anywhere else on the page layout.  That way you won't loose sections you might want to recover/reuse.  Of course they are unlikely to be where you want them, so move them as appropriate.

You can move an includelet into the "Scratch" area and it will be retained (indefinitely), otherwise move any unwanted includelets to the "Trash" column and next time you publish the page it will simply disappear.

Have you tried testing what you want to do in the test site, by "playing in" the sandpit for you site?  This is a really useful tool provided by Joe.  It is the usual URL with ":4430" added at the end.  It will be a mirror image of the live site, but nothing ever gets formally published and no emails are ever sent out from it. However, you can still publish a page and see what the changes you are proposing will look like.  In effect, you can play around with concepts without affecting your live site/data.

Good luck

Alan (Euphonix Choir)