Microsoft Excel 2003

• 1). Launch Excel 2003, then open the Excel workbook you want to share with other users on the network.
  
  
• 2). Click the "Tools" option on the menu bar, then click "Share Workbook." Wait for the "Share Workbook" options dialog window to appear.
  
  
• 3). Click and enable the checkbox next to the label that reads "Allow Changes by More Than One User at the Same Time. This Allows Workbook Merging." Click the "OK" button.
  
  
• 4). Click the "File" > "Save" option on the menu bar to save the permission changes to the workbook.
  
  

Microsoft Excel 2007 or 2010

• 1). Open Microsoft Excel, then open the workbook you want to share.
  
  
• 2). Click the "Review" tab on the "Office Ribbon," then click "Share Workbook."
  
  
• 3). Click the "Editing" tab, then enable the checkbox next to "Allow changes by more than one user at a time. This also allows workbook merging."
  
  
• 4). Click the "Advanced" tab, then select options for tracking and updating changes to the shared workbook. Click "OK."
  
  
• 5). Save the workbook to save the sharing and permission changes for the file.