Fernandito, if you flip the board over you still must work from right to left. The reason for this is that the cutter is forcing the board against the fence going that way. If you go the other way the bit will push the wood away from the fence and it will be very difficult or impossible to control. The only way it can be done safely and accurately is if you clamp a board onto the table on the opposite side from your fence so that you have 2 fences and your work is trapped between them. When you go from left to right the board you clamped to your table becomes the new fence.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.