Silvie, as Gidett said, the two vent/filler hoses are next to each other attached to the left side rear off the tank, these held on with metal clips that can be manipulated with your fingers. You can take off your let side plastic and the tank securing bolts and have your partner lift the tank slightly and fit your hand under it to put it back in place if it came off. I suggest you do this with a minimal amount of gas in the tank. I just had my tank off so I could remove the air box, clean the filter, and change the plugs, this being my first venture down this road. If by yourself, you can use a piece of 2 x 4 to support the tank. I did not take mine off all the way, leaving the wiring, vent tubes and fuel line in tact, but did pull it back enough to get the tank off the rubber mounts by the front, and secured the tank partially on its side with bungies and partially resting on the frame. My only caution, having read that a few people had done this, is that if you leave it on and work around it, be careful not to allow the plastic fuel line connector to become damaged. Also, when re-installing, be careful that there are no loose wires or wiring harnesses sitting on the spots where the tank rests. My bad, you have to take off a lot of plastic on both sides to get the tank off and be able to see the area where the hoses connect.
2009 Versys (Mine's Green)