@gato_q123 your question is different from the original poster, you may want to start a new topic.
Most reviews are automated and not really considered an "audit". You get a letter saying something like "we don't think you qualify for this credit, we think you owe $$ more tax" or, "we think you forgot to include some income and you owe $$ extra tax."
In that case, you have 2 main options. If you agree with the assessment, you write back saying you agree and you pay the tax. If you disagree with the assessment, you write back and say you disagree and provide proof. If the IRS is partly correct (let's say you forgot to report some income but you also have offsetting expenses) then your proof might include an amended return to demonstrate the calculation of the tax you believe you owe after considering both the income and the expense changes.
If you are asking about the first situation, where you agree with the IRS assessment of changes to your tax return, there is no particular harm in sending an amended return but no particular benefit either. If the amended return disagrees with the IRS calculation they will either ignore it, or it will start a new round of letters back and forth to clarify what you owe.
If you are asking about the situation raised by the original poster, where you have an actual audit (by mail or in person) and the IRS makes a determination against you, you can't appeal that by filing an amended return. You can only appeal the results of the audit by appealing to the auditor's supervisor or taking the case to Tax Court.
