Another, albeit slightly more technical, solution is to look at the fuse compartment underneath the steering column. Simply open the compartment, remove the sliding door fuse (fuse J11), and swap it for one of the other fuses of the same type. That could fix the problem!
Regardless, be sure to tell the rental company something is wrong with the door. If it’s something more serious, like the sliding door actuator, it must be serviced by a professional.