It is common practice for companies to make two allowances for doubtful accounts:

$1.$ The specific allowance is based on accounts the company has reason to suspect may not be paid.

$2.$ The general allowance relates to accounts as yet unknown but that experience suggests may not be paid. The likelihood of a receivable account being unpaid is usually assumed to increase the longer it remains unpaid, and many companies determine a general allowance as a percentage of overdue receivables, with an increasing percentage being applied against wiel longest overdue accounts.

You are aware that CAS $540$ Auditing Accounting Estimates, Including Fair Value Accounting Estimates, and Related Disclosures is likely to be relevant to the audit of the allowance for doubtful accounts

Describe the procedures you would adopt in verifying a specific allowance for doubtful accounts

please give brife and simple answer