A LoyAcctRef is a set of identifiers that refer to a specific loyalty account record. At least one of the optional elements should be specified. The id of the loyalty account as maintained by, and usually generated by, the loyalty system of record. The card number being searched when searching for a specific loyalty account. The card number could be the same as the account_id. There could also be more than one card associated with a single loyalty account. This type can hold a string of max length of 32 characters.