Restore Thread with isDeleted = true

[setcookie]

For some reason the thread is flagged with = true. I need to set that
parameter to = false again so i can retrieve the posts from that
thread via the API. How can set it to false? Does thread restore do
that and only that or is there another way? I dont want to loose the
comments and dont want to see properties beeing changed.

Im actually wondering: If i remove a Thread with Thread:remove is set
it to isDeleted = false but the thread is still there. So how can i
kill a thread for good?

Thanks

set*