To find or replace styles, you have to display text in the source pane (Text editor pane), and make tags visible.

Locate the tag name you want to replace. Locate also the name of the replacement tag.

Insert tags in the Find or Replace box, by using the same tag insertion command you use to insert tags in the text. In the standard configuration, it is attached to the key F9.

Select other find and replace options, and then click OK.