An appraisal report is the result of an agreement for services between appraisers and their clients.  What can be done with the report, and who the appraiser can communicate with are established by these two parties.
In the majority of real estate transactions, the appraisal is ordered by the Lender. In this case, the Lender becomes the appraiser’s client, and the establishment of the report’s Intended Use and Users will be arranged at the time of assignment.  The appraiser must take care to protect the confidential nature of this appraiser-client relationship. While it is common practice for the Lender to charge their borrowers an “Appraisal” fee as part of their closing costs, this is a separate agreement between Lender and Borrower, and does not infringe upon the Lender’s appraiser-client relationship.
However, a borrower is entitled to a copy of the report – it’s usually included with all of the other closing documents. The lender is required to disclose and provide this information to their borrowers as part of the lending process, to comply with the Dodd-Frank Wall Street Reform and Consumer Protection Act (Dodd-Frank Act): Disclosure and Delivery Requirements for Copies of Appraisals and Other Written Valuations Under the Equal Credit Opportunity Act (Regulation B) | Consumer Financial Protection Bureau (consumerfinance.gov)
As a homeowner, if you find you are in need of an appraisal, the best option is to engage an appraiser directly. In these cases, the appraiser will work directly with you and establish how the appraisal can be used based on your intended use and the scope of work requirements, whether it be for PMI removal, estate planning or tax challenges, for example.