From the Approval History program:

In the Approval History program (System Administration > Workflow Administration > Approval History), click Search
Enter search parameters and click Accept
1. If you want to search a particular date range, you can separate two dates with a colon (i.e. XX/XX/XXXX:XX/XX/XXXX)
Select the Excel button on the ribbon
Confirm the desired columns to included in the report and click Accept to export the report to Excel

From Workflow Central:

In Workflow Central (System Administration > Workflow Administration > Workflow Central), click History
If desired, narrow down module and timeframe in the top two dropdown fields
Click Excel

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