I need to rmove (undo) a baseline. How do I do this?

All you need to do is right click on the project and resave that baseline.  It will then be overwritten with the new dates.

What do I do if I want to totally remove the baseline? (and show no baseline?)

There is no formal function for this, but you can save the project as a template and then create a new project from that template. This will remove the baseline entirely.

Thank you Josh.