If you need to correct a transaction from a prior accounting period you will need to perform the following:
- Open every accounting period closed in order of newest to oldest.
- Un-post and repost the transaction you would like to fix.
- Close each accounting period in the order of oldest to newest.
For example lets say the current accounting period is 2012-12 and you want to correct a transaction in 2012-10. You will need to do the following: