It states on their Hurricane Irma Travel Advisory that you have a 14-day window to rebook a flight to the same city-pairs without a price increase. Unfortunately, this policy doesn't work for you because the event you are to attend was rescheduled outside of this 14-day policy.
You say you don't fly much on SWA, but it looks like in this case you will be finding another trip to use the points. Just watch that you don't wait so long that the points expire. But, that's another issue.
From the SWA website:
Travel Advisory
Hurricane Irma
Southwest Airlines is closely monitoring the projected track of Hurricane Irma and possible Stations that may experience operational disruptions (flights may be delayed, diverted, and/or cancelled) in the coming days. Before you head to the airport, please check the status of your flight for the most up-to-date information.
Customers who are holding reservations for the effective dates and cities listed below and want to alter their travel plans may rebook in the original class of service or travel standby (within 14 days of their original date of travel between the original city-pairs and in accordance with our accommodation procedures) without paying any additional charge...(cont.)