You need to be in seller hub where there are options to update many aspects of your listings. Just select 'active listings' and then edit.
https://www.ebay.co.uk/sh/lst/active
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)