1. Open the worksheet that you wish to change or remove the password for. Enter the password when prompted.
2. Select the 'File' menu to open a left-hand menu pane.
3. Click 'Info.'
4. Click 'Encrypt Workbook' next to 'Permissions.' Another menu will show up.
5. Choose 'Encrypt with password.' A password encryption window will appear and the other menus will close.
6. Remove the password by clearing the 'Password' field and selecting 'OK.' Modify the password by typing in a new one in the 'Password' field, then selecting 'OK.'