Stand-by at no cost would not be an option since you are changing connecting cities.

You could do a Fly-Now, if M-class is available all the way through (presently showing M9/M3), and if the 'system' will allow it. Since nwa.com won't allow it as a bookable option, that might not suggest good things. Still showing P8F8 on the IND-LAX leg and P9F9 on the LAX-LAS leg would suggest good shot at the upgrade on both legs though if you could make it work.

I'd suggest setting your alarm for 4:20 am on the 22nd and go to nwa.com and see if it gives you that option.