How delete a slug?

Hi, I had install a plugin (wp-members), and need to place a page were members can modify theirs data. The plugin requires to create a page with a slug named members-area to members do it. Infortunally, I did a mistake when I create the Members page, but writing something wrong inside the page, so later I delete that page. Now I have create a new page Members, but when I named the slug like members-area, WP chance it to members-area-1. And for this reason, the plugin doesn’t work, the slug must be members-area. I tried again, and got members-area-2. So, how can I fix this?