Merging or otherwise controlling one's own bugs on debbugs.gnu.org

[Jens Schmidt]

In 

  https://yhetil.org/emacs-bugs/87r0mj75ci.fsf@sappc2.fritz.box/

I tried to (force)merge my own bug to somebody else's using control
messages.  Which showed no visible result.  Then I tried to close it
with the additional fixed-in-version information:

  https://yhetil.org/emacs-bugs/87o7hn74nc.fsf@sappc2.fritz.box/

Again, without result.  (I finally closed it by sending to the
NNNNN-done@debbugs.gnu.org address.)

Was there anything syntactically wrong with these control messages?

Would there have been any difference if I sent them to the debbugs
control server, and not to NNNNN@debbugs.gnu.org?

Are such control messages reserved for list admins?

If yes, how would I request a change in bug status?

Is there any documentation on that topic except what is on

  https://debbugs.gnu.org/Emacs.html
  https://debbugs.gnu.org/Advanced.html

Thanks.