There is a function to Search and Replace one ingredient for another. Specifically:
1. Close any open Recipe.
2. Go to the "Database" ribbon and select "Search and Replace". For versions prior to version 11 click Database>Search and Replace
3. In this dialog, search for the specific item you wish to replace in the upper box (Search For). Likewise, search for the specific item you would like to substitute in the bottom box (Replace With).
4. Upon execution (OK), the program will straight swap the Search For item with the Replace With item.
NOTE: The search and replace affects all Recipes and is irreversible. The amount & measure of the original ingredient is retained with the replacement ingredient.