For this example, I'll quote Theymos's post to this topic.
Step1 - I seek the sources that I'll quote in the history of Theymos's post.
Step2 to 3 - Then I copy the quote link in a new tab and change the source topic link that I marked above
with the number of the OP link (in this topic).
Step4 - Then click enter
And I managed to quote Theymos locked posts cheers
I hope this helps to claim ownership of someone's account in the future.
You should be given an email address in the error message. Send an email there and you will be given further instructions.
~snip~
Edit...
Maybe, the post label also need to be changed
Sorry for my bad English, I hope these pictures help you understand what I mean .