Update Posted Records 

When you are managing your General Ledger, you will be posting records. Most of the time once you post a record, the data is locked.  You will not be able to update the source record or any transactions associated with the posted record.  This is the case for the majority of fields on the Accounting Seed source objects, but there are several that can be updated. 

The below chart shows what fields can be updated after posting.  Any custom fields that you have added will also be updateable.