A more thorough explanation:

A merchant appraiser is an expert who is appointed by a customs officer to reexamine and revalue imported goods for customs purposes. This person is usually an experienced merchant who deals in or has dealt in goods of the same type and quality as those being appraised. An appraiser is only appointed when an importer requests one.

For example, if a company imports a shipment of electronics from another country, they may request a merchant appraiser to reexamine and revalue the goods to ensure that they are being charged the correct amount of customs duties. The appraiser would be someone who has experience dealing with electronics and can accurately assess their value.

Another example would be if a company imports a shipment of clothing. They may request a merchant appraiser who has experience in the fashion industry to reexamine and revalue the goods. This ensures that the company is not overcharged for customs duties and that the value of the clothing is accurately assessed.

These examples illustrate how a merchant appraiser is appointed to ensure that the value of imported goods is accurately assessed for customs purposes. The appraiser's expertise in the specific type of goods being imported helps to ensure that the correct amount of customs duties is charged.