I know, I know... RTFM. However, I accidentally reported a game result that my opponen already reported. So now there are two entries for one game.
Is it possible to remove one of them, please? I promise to not do it again.

No apologies required. A simple mistake easily corrected. Here's what you do:
a) Click on Member page
b) Scroll to the bottom of the page where your results are listed.
c) Find the erroneous entry and click the delete button on the right hand side.
d) Enter your password when prompted and hit okay.
All cleaned up.

'Delete'... I wonder what that button does...
*sigh*
'Delete'... I wonder what that button does...
*sigh*
LOL, do not feel bad. It's a very common question.