You will need Full Financial Permissions to reform this function.
How to Access a Closed Batch
Go to Contributions > Batches from the left navigation.
Locate the Filters button on the right.
Then select the checkbox next the "Closed" label > Search
Reopening a batch
To reopen a batch, navigate to a closed batch and select "Reopen batch" in the "Actions" menu. A pop up will appear asking you why you are reopening the batch. Once you provide the notes and click "Reopen," the batch will once again be editable.
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If this batch was posted to accounting. all register entries that were added to the general ledger will be deleted thereby undoing the previous posting.
Reopening in bulk
Just like closing multiple batches in bulk, you can also reopen multiple from the batch listing screen. First, you will need to clear the filters on the table (or filter only for closed batches) to find the closed batches you want to reopen. Then select the ones you want to reopen and choose Bulk Actions > Reopen.
Note: if any closed batches were posted to accounting, any resulting register entries from that posting will be deleted from the general ledger thereby undoing the previous post.