Once a note has become read only, either by being manually or automatically locked, it cannot be reopened to allow changes. 

If you need to make a change to a read-only note, you can use the below workaround:

Open the note that you'd like to edit, and copy the content of the note

Click Create then Note

Paste the content from the read-only note

Make the relevant changes and additions

You could create a new note keyword called "edited" which you can associate with the edited note so that you're aware of which is the old/new version of the note

Click Save and Exit

Updated on: 25 / 11 / 2020