A more thorough explanation:

A recall letter is a type of letter that is sent to either a government official or a consumer, requesting them to take action on a particular matter. There are two types of recall letters:

A letter of recall is a document sent from one nation's executive to that of another, summoning a minister back to his or her own country. This type of letter is usually sent when a government official is needed back in their home country for urgent matters. For example, if a country is facing a crisis, they may recall their ambassador from another country to help deal with the situation.

A manufacturer's recall letter is a letter sent by a company to its customers, asking them to bring back a product for repair or replacement. This type of letter is usually sent when a product has a defect or safety issue that could harm the consumer. For example, if a car manufacturer discovers that a particular model has a faulty part that could cause an accident, they may send a recall letter to all the owners of that model, asking them to bring their cars in for repair.

Both types of recall letters illustrate the definition of a recall letter, which is a letter that is sent to request action on a particular matter. Whether it's recalling a government official or a faulty product, the purpose of a recall letter is to address an issue that needs to be resolved.