I'm an Alaskan who rescinded my UW application due to residency problems (I'm currently in med school in NYC, of all places--and I REALLY wish I was back home!)
UW and the Alaskan government are both very strict about the residency requirements. I had maintained my alaska residency as a student in Seattle for 4 years (planning to apply to UW as an Alaskan resident), then had to take on Washington residency because I got married and remained in Seattle for the 9 months prior to med school. To sum it up, Alaska wouldn't let me apply as an Alaskan resident, and UW wouldn't let me apply as a Washingtonian, even though I'd lived in Seattle for four years (and was working at UW hospital!), as my WA residency had been in place less than a year.
The policy is so strict because it is the state government that pays the difference between in- and out-of-state tuition. For those of you that don't know, Alaskans are required to pay back one year of in-state service for every year AK subsidizes your UW tuition. This policy is new since 1998. WA students are not required to pay back time. I don't know about ID, MT, etc.
One of my best friends is at UW in WWAMI, from Montana. She has had to maintain very strict records of her state citizenship, and it has been difficult as she recently married a Washington resident. She has to maintain Montana status, though, or they will not subsidize her UW tuition.
Finally, each year they allocate a specific number of slots for students from each state, and you are accepted to UW out of that state pool. For some states, it can actually give you a leg up--I think the WA acceptance rate is ~1/7, while the AK rate is ~1/4 (at least, that was for the year I applied to med school). As they have a specific number for each state, it is highly unlikely that they will allow you to switch.
So, if you could work it out, that would be great, but my guess is that even if they DO allow you to switch residency status, which is highly unlikely from the WA end (the state will have to take on your tuition), it would be an enourmous amount of red tape. Trust me--I speak from experience with trying to communicate with the WWAMI offices.
good luck!