You cannot directly edit an opening balance.
To edit an incorrect opening balance, you will just have to adjust the balance of the account by posting manual journals. You need to manually go to the respective accounts and make the changes.
When you make such a journal entry, there will be an opening balance adjustment entry created automatically.
In order to make the opening balance adjustment account nil, you will have to post manual journals against other accounts using this account. ( which is mentioned in the adjustment )
Online accounting software
for small businesses.