Hello.
You should be able to get the current document that you want to update, change your notes value with the new ones to be added bye the user, and then make and update petition to Solr to delete the old document (findable by the id that you include in the POST petition) and add the new document with the changes done. Try to develop a small Java application with SolrJ resources, for example. Depending on the number of update petitions that your system/application will do I recommend you, or not, to include a commit order after the update one. Also you can configure a periodic auto-commit to update indexes automatically.
