Method for switching over a gas turbine plant from gaeous fuel to liquid fuel and vice-versa

The invention refers to a method for switching over a gas turbine plant from gaseous fuel (16, 20) to liquid fuel (18, 22) and vice-versa, wherein the gas turbine plant comprises a first combustor and a second combustor fed with the flue gases of the first combustor. The method comprises sequentially switching over the first and second combustors while the other combustor maintains its operating conditions.