1. Open the workbook.
2. On the File menu, click Save As.
3. On the Tools menu, click General Options.
4. In the Password to open or Password to modify box, double-click the asterisks.
5. Type the new password (password: A way to restrict access to a workbook, worksheet, or part of a worksheet. Excel passwords can be up to 255 letters, numbers, spaces, and symbols. You must type uppercase and lowercase letters correctly when you set and enter passwords.), and then click OK.

   Important  Use strong passwords that combine upper- and lowercase letters, numbers, and symbols. Weak passwords don't mix these elements. Strong password: Y6dh!et5. Weak password: House27. Use a strong password that you can remember so that you don't have to write it down.

6. When prompted, retype the new password, and then click OK.
7. Click Save.
8. If prompted, click Yes to replace the existing workbook.

Note  If you have protected a shared workbook (shared workbook: A workbook set up to allow multiple users on a network to view and make changes at the same time. Each user who saves the workbook sees the changes made by other users.) with a password, you can't change the password without unsharing the workbook, which deletes the change history (change history: In a shared workbook, information that is maintained about changes made in past editing sessions. The information includes the name of the person who made each change, when the change was made, and what data was changed.).

1. Open the workbook.
2. On the File menu, click Save As.
3. On the Tools menu, click General Options.
4. In the Password to open or Password to modify box (or in both boxes), double-click the asterisks and then press the DELETE key.
5. Click OK, and then click Save.
6. Click Yes to replace the existing workbook.