My topic has been blocked and I would like to make the changes to pass the moderator review, but there's no such option.

In the same menu, there must be a "report" button.
When you hit it, you must be able to write to a moderator about your reasons as to edit and perhaps reopen that topic.
It's usually easier to start a new one, if you have an understanding why your previous thread was locked. If you do not seem to have that understanding, there is an old thread in this board about moderation questions... If it's not locked yet:)