Use the Find/Change
dialog box to find all instances of a particular style and replace
it with another.
Choose Edit > Find/Change.
For Search, select Document to change the style throughout
the document.
Leave the Find What and Change To options blank. If the
Find Format and Change Format boxes don’t appear at the bottom of
the dialog box, click More Options.
Click the Find Format box to display the Find Format
Settings dialog box. Under Style Options, select the character or
paragraph style you want to search for, and then click OK.
Click the Change Format box to display the Change Format
Settings dialog box. Under Style Options, select the replacement
character or paragraph style, and then click OK.
Click Find, and then use the Change/Find or Change All
buttons to replace the style.