This from E-Bay help pages
To revise your listing:
Click My eBay at the top of most eBay pages.
Under My eBay Views, click Selling. Your active listings are displayed.
Selling Manager and Selling Manager Pro subscribers: Use the Active view within My eBay.
In the row for the item you want to change, from the Action column dropdown menu, click Revise.
On the 'Revise your listing' page, make your changes. (Any grey sections can't be revised.)
Click Save and Continue.
If you cant change the title then you will have to update the item description and highlight the error and make it VERY noticeable