The impulse answer is to do a short sale. However, to do a short sale, you must have a "hardship". A few examples of hardship are medical expenses, reduced income, and having to move for a job. Having to move for a job can be within the Seattle area, if the job requires an extra long commute that puts a "hardship" on you.
If you are moving up to a larger home, it might even be strategically smart to bring cash to closing, so you can close and buy the more expensive home. The reason this can work to your benefit is because if houses are appreciating at 10% annually, the $300,000 home goes up $30,000 and the $500,000 home goes up $50,000.
Each situation will require specific analysis. If neither of the above two options work for you, you stay in your current home until it appreciates enough for you to have positive equity. You may want to see if you fit one of the refinancing programs, so you can get your interest rate down to today's still record low rates.
If you don't have the funds, you need an agent with a solid track record of closing short sales. You need to commit to the process and cooperate with all the documentation requests in a timely manner and get legal counsel as to the effects the short sale will have on your credit and how it may affect you.
If you are asking for a way to sell a home for more than it's worth, that becomes tricky. What a home is actually worth is what a willing and able buyer and a ready and able seller agree to. If the buyer needs financing, as most do, the appraiser will have some influence over the final outcome.
Depending on where the property is, the level of demand for similar homes in the area, it's condition and the seller's capacity to maximize the marketability of the home you may get close.
You need an experienced and seasoned Pro to help in the process. This is not a job for someone just starting out or someone who hasn't kept up with the best marketing methods.
I hope this answers your question.
If they do recommend a short sale, give me a call at 425-681-8364.