While editing or deleting entries, if you receive the error message "Client error: Invalid text encoding: Cannot display non-Unicode posts unless default encoding has been selected", see http://www.livejournal.com/support/faqbrowse.bml?faqid=133.
Remember that once you edit or delete an entry, there is no way to reverse this. If you delete an entry, any comments left on it will also be made inaccessible. If you think you might change your mind, you should save the text elsewhere before making the change.
USING THE WEB INTERFACE:
Go to the "Post Comments" or "Read Comments" page for the entry you want to edit. You can get to these pages by clicking on the entry's comment links if comments are enabled, or by using your Calendar view). Click on the Edit Entry button (a blue pencil icon) on the small blue toolbar near the top of the page. This will take you to the Edit Journal Entry page.
From there you can make the changes you want. To edit an entry, make the changes to the text and then click "Save Journal Entry" to save your changes.
To delete an entry, click the "Delete Entry" button. You can also delete the entry by deleting all the text from the body of the entry and clicking "Save Journal Entry."
You can also get to the Edit Journal Entry page by using http://www.livejournal.com/editjournal.bml. This page allows you to choose an entry to edit either from your most recent entries or from a specific date.
USING A DOWNLOADED CLIENT:
Many clients available for download can edit and delete journal entries. For information on a specific client, consult its documentation or its menu options.
Can I edit/delete an entry in a community journal?
How does my Calendar work?
What is a downloadable client? Where can I get one?