So there was a receivable you once considered was partly uncollectable. Be the reasons what they are, as it happens, you’ve accounted for the write down (note that you haven’t written the receivable off, but just merely down; that is you’ve accounted for an allowance against the positive asset thus diminishing your assets in total by the amount you considered you will not collect from your customer).
Obviously there may be occasions where your customer in fact may find the money and pay you in full still. For an example let’s say that the full receivable was 1,000 CU, the allowance 700 CU and the remaining receivable then 300 CU. Now the customer has paid us 1,000 CU (yes, with a considerable delay but as they still want to continue in business, they were able to pull themselves out and find the money). Your accounting entry then would be as follows:
|1||Debit||Allowance for doubtful receivables||700|
|Credit||Doubtful receivables expense||700|
|2||Debit||Cash and cash equivalents||1,000|
With the first entry you show that the allowance was reversed as you in fact received the balance in full. Note that the allowance expense is reversed on the same account as the initial expense was accounted for on the income statement.
As you had the receivable itself in the full amount, it’s shown as a regular collection of receivables with the entry number two.