Can a Geass be removed?

[danny-roboguy.livejournal.com]

We all know that a Geass effect can be cancelled, but can a Geass itself be removed or negated without the possesor being killed or a transfer of the Code?

So far the only solution I've came up with is if Lelouch commanded another Geass user to never use his/her geass ever again. What do you guys think?