Legal analysis: changing the approved collection into audit collection requires that the accounts and vouchers are sound and the income, costs, expenses and profits can be accurately calculated. There is generally no requirement for income, but some places have set a lower income limit as a management measure. First of all, it is necessary to submit accounting vouchers to prove that income, costs, expenses and profits can be accurately accounted for, and then it is necessary to provide an application for approving the change of collection to audit collection. It's best to ask the tax department for on-the-spot investigation and verification.

Legal basis: People's Republic of China (PRC) Tax Collection and Management Law.

Fifth the State Council tax authorities in charge of the national tax collection and management. The local State Taxation Bureau and the local taxation bureau shall conduct tax collection and management respectively according to the scope of tax collection and management stipulated by the State Council. Local people's governments at all levels shall strengthen the leadership or coordination of tax collection and management within their respective administrative areas according to law, support the tax authorities to perform their duties according to law, calculate the tax amount according to the statutory tax rate, and collect taxes according to law. All relevant departments and units shall support and assist the tax authorities in performing their duties according to law. No unit or individual may obstruct the tax authorities from performing their duties according to law.

Eighteenth taxpayers should use the tax registration certificate in accordance with the provisions of the competent tax authorities in the State Council. The tax registration certificate shall not be lent, altered, damaged, traded or forged.

Article 19 Taxpayers and withholding agents shall set up account books and keep accounts in accordance with relevant laws, administrative regulations and the provisions of the competent departments of finance and taxation of the State Council, and conduct accounting according to legal and valid vouchers.