Transactions were posted to the wrong expense account over a several month period. Can I select them somehow and update them as a group?
Follow the below steps,
This tool is available for Accountant User you instruct your accountant or login as accountant user.
The tool is Reclassify transactions.
Go to the top of the screen - select Briefcase icon - reclassify transactions - Relevant period,Profit & Loss accounts - select the relevant expenses from Accounts heading - Transaction heading, Name if required select all, show transactions select non-item-based, include journal entries , Accounts show select selected account ( If ALL selected then Name need to be specific ) - with single click from top radio square button select all the transactions - bottom select For all selected transactions, change - Account to select the required account to reclassify from drop-down arrow menu - click the Blue button Reclassify.
Note - Only non-item-based transactions can be reclassified, the item-based only class can be reclassified.
Comment back for further clarifications.