You can edit any tags in the feed - I assume you are thinking about the 'itunes:subtitle' and 'itunes:summary' tags specifically - and the changes will appear in the Store after a couple of days.
Of course if you add new episodes, they will have their own subtitle and summary tags, and the previous episodes will still be in place with their own tags, which then presumably wouldn't need editing - though you could alter the tags for the entire podcast (showing in the 'Description' on the Store page).
This page demonstrates which tags appear where in the Store and when subscribing:
All changes have to be made in the feed: you can't edit anything in iTunes itself.
Thanks Roger but my problem is that i dont know how to manually access the feedburner feed to edit.
Now each episode is getting the same tags from the smart cast option.
See how the artist name is the same as the author
I'm not sure what it is which is wrong - the 'itunes:author' tag populates the two places in the Store page I would expect it to: but in any event the feed:
is drawn from a Blogger feed and it is that which you need to edit, then the changes will make their way through Feedburner to iTunes. If Feedburner is adding or changing tags from the original feed then there will be settings for you to change that but I can't advise on the specifics: you won't be able to access the actual feed itself.