Best Answer Rob , 30 June 2013 - 02:56 PM
The best, and only practical way to accomplish this is by manual post management. In other words, you go to your latest post, edit it, and copy the entire content of your post, pasting it into the Excerpt field.
When you write your next post, go back into that last one, and trim the content of the excerpt field to the first one or two sentences.
For each new post, copy and paste the content to the excerpt field, and just remember to trim the last one when you post the next new one, or you'll have multiple posts with full excerpts.
Unfortunately, we don't have a plugin yet that will do this kind of excerpt management.Go to the full post