Electric Company Security Deposit Refund

Helping a friend with her books.  Her electric company security depost of $1,000 was recorded in QBO as a current asset in 2018.  In 2019 the electric company applied the $1000 deposit towards the August bill.  The balance of that months bill was paid. She does not input her monthly utility bills into QBO.  She does download all of her bank transactions so only the payments made towards the utility bill is recorded each month.  Her Chart of Accounts still shows a $1,000 balance listed for the current asset - Electric Security Deposit.  What steps do I take to get the balance to $0?  I am assuming a journal entry would apply here.  I know I would credit the Security Deposit,  but I am not sure what account I should debit.