For what it’s worth, Starwood did split up my existing 2 bedroom L/O reservation at SDO into two reservations – one for the larger unit that I deposited with SFX and one for the smaller unit that I deposited with II.
It’s my understanding that if you cancel a portion of your reservation less than 60 days prior to your arrival date, the StarOptions associated with your cancelled unit are still available for use, but you are limited to only making a reservation using them within 60 days of your new reservation’s planned arrival date.
In particular, mystarcentral.com says:
“If you cancel 60 days or less prior to the check-in day you will still be able to make reservations during that use year, but only to reserve a vacation that is within 60 days of the arrival date. “
If you would like a longer reservation window, consider depositing your smaller side week with SFX (if Starwood will split your reservation into two reservations). Here is a link to info on the current promotion they are running that will "give" you 3 weeks in exchange for depositing your one week at Kierland. The deposit deadline under this deal is January 31, 2007.
http://www.sfx-resorts.com/mail/sfxadclick.asp?
If SFX takes your week, you’ll have 3 years to use your SFX exchange week and a year from the deposit date to use your two SFX bonus weeks.
Other Tuggers have reported that SFX will take the smaller Westin Kierland unit since it has a separate living room and bedroom. Tugger reviews of SFX's inventory and (lack of) customer service are mixed, but if you are willing to give 'em a try with the understanding that your options are limited anyway, you may be pleasantly surprised.
Good Luck,
-nodge