coolangel, it is not a "law" but a is a requirement for appraisers. USPAP governs appraisers and how they are to complete an appraisal. The state boards can fine, revoke, or do a number of other things that are not pleasant to appraisers if they do not adhere to all guidelines of USPAP.
Jan 1, 2004, the guidelines changed in regard to reassigning appraisals. It is in regard to teh appraiser/client relationship. Even with permission an appraiser can not change the name and give it to the new lender. The only alternative an appraiser has is to do a new appraisal. Even if the new lender has a copy of the old appraisal, he can not discuss that appraisal. He has to order a new one. Getting a release does not work anymore.
Advisory opinions 25, 26, and 27 of USPAP address this exact problem....