I see a number of cases that involve first party insurance claims under property and casualty insurance policies. This is an area of practice that strongly benefits the insurance company and should be approached with great caution by the insured. The appraisal process is set forth in most policies. It is supposed to be a shorter, more cost effective way to handle the claims process. The appraisal process has nothing to do with whether a claim is covered in the first place. It typically involves a dispute over the amount it will cost to replace or repair damage.
Either party has the right to request an appraisal. If either party requests an appraisal, each party selects an appraiser. The appraisers then get together and select an umpire. Each appraiser then makes his case to the umpire and the umpire selects a figure.
If you are going through the appraisal process you should consult a public adjuster or an attorney. It could make a huge difference.