Is the previous period in a closed year?  If it is within your accounting period 1-24 you can just roll the period back and edit accordingly.  It the period is in a prior year you cannot roll it back without restoring a backup which would lose your activity entered since that backup was taken.  You would book the entries to Retained Earnings if they affected the income or expense accounts and date it 1/1.

You may not have permissions to edit previous period's transactions. Sage 50 allows 2 years to be open, if you closed your 2023 to open your 2025, then you will not be able to edit the transaction and you will need to make journal adjustment entries... Go to "Tasks" at the top of your Sage 50, select "system" and then select "Change Accounting Period". You will see the list of your open periods, there should be 24.