In order to write off the $2,200 amount as an uncollectible account there is one entry that the bookkeeper needs to make.
The entry will be a debit to bad debt expense for $2,200 and a credit to the allowance for uncollectible accounts for $2,200. What this entry will do is remove it as a contra-asset amount in the allowance for uncollectible accounts and charge it as an expense.