If you don’t agree with a charge (if you think the charge is not correct on the account you are reconciling), you mark it as a variance. You remove the amount of the charge you disagree with from the total of that Ledger Account to Certify amount. For example, if you have a ledger account that has a total of $500, but you disagree with a $200 PO that was charged to this account (it should have been charged to another account), you would put $300 in the Amount to Certify and a Variance of $200 will show.
The Preparer or the Approver can mark a variance. It will route back to the Prepare to ensure the correction is made. The Prepare can make the correction or they can communicate with another person to make the correction.
If you Send Back the Account Certification, it will go back to a Central Finance queue. You should only Send Back if you are told to by someone in Central Finance.