Despite the similarity between the two problems, it is preferable in this case to start the analysis from scratch rather than restart from the Isotropic Porous Media Tutorial solution.
To clear the existing solution, select Clear Solution... from the Solution menu and click Yes in the Clear Solution dialog.
To re-initialize the solution, click on the (Initialize Solution) button in the toolbar and then save the simulation.
(Initialize Solution) button in the toolbar and then save the simulation.