We all know that the days of holds are over (this was a great convenience, and I miss it), however.....

It appears that if you search with "onepass reward upgrade" checked, and there is at least one available sometime that day (seach "all" flights), when you select a flight (that doesn't have an upgrade available), for example, you get this (i've highlighted the hold part):

>Review Ticket DetailsPrice Details:
1 Adults (age 18 to 64) $99.00
1 Upgrade Reward(s)
Additional Taxes/FeesTicket Taxes/Fees $10.30
Total Price and $109.30

Without redeeming your miles, this trip is currently available in First Class for a total of $594.30 for all passengers. Purchase this reservation without redeeming miles.

Flight Details:
Depart:
6:45 a.m.
Thu., Nov. 30, 2006
Phoenix, AZ (PHX) Arrive:
1:28 p.m.
New York/Newark, NJ (EWR - Liberty) Travel Time:
4 hr 43 mn OnePass Miles/
Elite Qualification:
2,133 /100% Flight: CO734
Aircraft: Boeing 737-700
Fare Class: Economy (W)
Meal: Snack or Brunch
No Special Meal Offered.


! Upgrade not available on CO734.


Continue to Purchase.

Continue to reserve. A credit card is required to hold your reservation until midnight Fri., Nov. 17, 2006.


Now I wonder what happens when you either try to reserve (hold) this, or indeed just book it (what is the unspecified upgrade reward?). Has anybody tried it?