Southwest Rapid Rewards - Can I hold a reservation with Southwest?

I see a flight I like, but am not sure yet. Can I hold it for 24hrs?

I believe that you can, since this language appears in some of the fare rules:

<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Purchase roundtrip tickets within one day of making reservations and at least seven days before departure. </font>

(Quoted from: http://iflyswa.com/hotfares/promotional.html )

Also, as a general rule, you can cancel a discount Southwest fare and receive a credit towards a future flight -- without any change fee.

That's cool that you can cancel a DISCOUNT FARE. What about PROMOTIONAL FARE- same thing apply?

Yes, you can apply ticketless travel funds to any new Internet booking until the funds expire, generally 1 year from the original purchase date.

There is another helpful rule that I believe derives from a general e-commerce regulation: You can phone in to cancel any online booking within 24 hours and request a full refund to your credit card. This is helpful for example when you goof up and get the origin and destination cities backwards, or you forget about leap year. Please don't abuse this loophole, since some of us mess up more than others and we need it. :-)

If you just need to change the date and the sale is still ongoing, you can use the Travel Center page to cancel your old booking, and within seconds those funds will be usable to pay for your new reservation. Doing it this way saves you the bother of making sure the refund occurs and it saves the time of Southwest's CSRs.