Again here's hoping the stupid questions are the easiest to answer!
After 'writing' automation on a particular track, later in the mix I find myself wanting to change some things but (too many changes to just 'undo') I don't seem to be able to either overwrite or, what I'd rather, eliminate earlier automation. I've tried deleting the automation track lanes, but they come back. I don't want to undo all the automation on all tracks just one or two. Is this possible or is it 'once done' never to be undone? I don't find clear guidance in the knowledge base in this area. I actually have tutorial videos, but they just kinda skim over how to do it, not how to 'undo' it later. I nice point in right direction would be most appreciated!
Thanks again guys, for all your help!

I guess what I mean by the track lanes coming back is the little squiggly lines around knobs a faders remain and when moved continue to 'snap back' to prior placement.

You can select nodes in the automation lane and hit delete. Or move them around, etc. If you right click on the line, you can delete the entire lane in the context menu. Is that what you did? I'm not sure what would make them come back from the dead. 
 
 

What DRanck said.  This used to confuse me, too.  If you hit the "minus" button next to the lane, it just hides that lane, but the automation still works on that track, you can add that same automation lane again and all of the automation will still be there.  You have to right-click the line, like he said, and say "delete all" or "clear envelope" to get rid of all the changes to the automation.

Thanks DRanck, Yeah, I don't either, and I hate to go through 224 measures of eliminating nodes. Maybe I'm thinking wrong, but theoretically, if I delete the automation lane, ie open it, select the lane, hit delete and it disappears, it should be gone. I reopen the console, hit play, grab the fader (on the track of which I just deleted the automation lane) pull it down a bit and let go, just release the 'left click' , and it pops back to where it was. Not a double click that would 'zero' the fader, just a release. ....and that darn squiggly line above and below the fader is still there. I really don't want to globally remove all automation from all tracks, but even that doesn't eliminate ALL automation written. Maybe I'm just doing something wrong...(which is usually the case)

Thanks Doc, I'll give it a try.

Sure, it all comes down to that "ie open it, select the lane, hit delete and it disappears" part.  If you're not right-clicking on the envelope or one of the nodes in the envelope and saying "delete envelope" or "clear all", the minus sign that says "remove automation lane" just removes the lane from view, it doesn't delete the automation changes themselves.

That explains a load! I have done that (hit the minus) plus hit the delete key on the keyboard, which may indeed be doing the same thing! Thanks again Doc and DRanck! Really appreciate your time!