You can use the Format Button in the Find and Replace Dialog box to replace font formatting. Use the steps in this tech-recipe to accomplish this.
1. Go to Edit | Replace.
2. Delete the existing text from the Find what and Replace with boxes.
3. Click in the Find what box.
4. Click the Format button, and then click Font.
5. Select the formats you want to find, and click OK.
6. Click in the Replace with box.
7. Click the Format button, and then click Font.
8. Select the desired format you want to apply to the text, and click OK.
9. Click the Replace, Replace All, or Find Next button.