Simulation Wizard aims to preserve the integrity of audit data. Consequently when a Simulation is linked to an audit, the user will not be able to edit the RED line equipment. Why not? Well it's a real audit featuring real equipment! Furthermore, if a user could edit the equipment on the RED line this would only giving Simulation Wizard ‘half’ the story (i.e. the equipment and not how it was used).
In conclusion, if you want to edit the equipment on the RED line of a Simulation you should not link the Simulation to an audit.
It's perfectly possible to create a Simulation not linked to an audit and then emulate the audit conditions (equipment, utilisation profile etc). Of course the Simulation is a hypothetical one rather than one intrinsically linked to an audit.