Night auditors may work alongside a security officer to maintain a level of security during late-night hours for both night staff and guests. In addition to balancing the guest ledger, the night auditor is usually responsible for balancing the city ledger and the advance ledger. The city ledger consists of money owed to the hotel by credit card companies and direct bill accounts. The city ledger also contains house accounts, such as management dry cleaning charges, or local phone call charges which are usually adjusted (written) off at the end of each month. The advance ledger is aptly named because it is a ledger for guests who have sent money in advance to either pay for or guarantee their stay. These funds are posted to the advance ledger when received by the hotel, and then transferred to the guests folio (in the guest ledger) upon arrival of that guest.