Dear Seeking Relief,
Yes you can have your taxes adjusted based on lower assessed value. Once adjusted, the Assessor will look at your value annually and either adjust it down further or up as the case maybe. This in no way threatens your Prop 13 protection (limiting your taxes to 1% of the value at time of purchase).
As the home eventually increases in value, the assessor adjusts you upward, but only until you get back to where you started. Then it is limited to the 2% annual increase just as before. In general the assessors of both Ventura and Los Angeles Counties are doing this automatically on all homes bought after 2004.
However, I am hearing of some folks who have to submit on their own. Forms can be found on line at http://assessor.countyofventura.org/ for Ventura and http://assessor.co.la.ca.us for Los Angeles. When you fill out the form you will be asked to provide some comps (comparative sales) as evidence that the property has declined in value. Fell free to visit my website or shoot me an email with your details, and I can get you the comps you'll need. There are services out there that will do this for you, for $99 fee, but this is totally unecessary as it's really easy to do.
Tim