Yes you can! You can search for all Records within a Category for editing or other purposes.
1. Go to the Main Menu > Records
Alternatively, go to a specific account, then under the first five Records tap on 'Show more'
2. Tap on the ^ at the bottom of the screen (above 'This month'), then 'Instant filter'. Choose whichever Category* you want, then tap on √.
3. When your desired Records are displayed, swipe gently right on each Record you'd like to edit, then tap on the pen icon at the top. When you have finished, save your changes with the √.
*Note: These instructions apply for Labels or other identifiers, not just Categories!