If you brought an odd year and you want to get an even year unit, do you return your odd year to Starwood and get an annual year from starwood. Otherwise, you will end up with an odd year and an even year contract. You will have to pay extra $20 for admin fees in the maintenance fees for each contract.
i have done this twice and each time was different. before i go into details you must get an explorer package. call kierland and tell them you want one. this will cost you $1995 +$99 fee. the $1995 will be used toward the downpayment of the new upgrade = you will receive 80,000 starpoints.
now my first upgrade i owned eoy even at westin kierland and i wanted to use my 1 year option to purchase the other half for the same price it was the year before. but they did not have my unit available eoy odd so they sold me a separate unit. so i know 2 separate deeded timeshares at kierland.
they would not give me any incentive starpoints for the upgrade. but it was a great price so we did it. the downside to this is they are treated as separate units, so if i want to borrow in 2007 they will take it out of my 2009 unit not my 2008 unit.
when we upgraded our VV, we owned eoy odd in the bella section of VV and they upgraded us to an EY unit in the key west section. they bought back the bella unit at the same price as an eoy unit and i paid the difference for an every year. again they would not give us a sales incentive but i had the explorer package and got the extra starpoints.
i am presuming you bought the original from the developer, if you didn't then it could be a completely different story. you would have to buy the upgrade and requalify the other half.
they can only upgrade if they have the inventory.
good luck