I received a below average rating as a result of a forced distribution system at my company. This triggered a coaching plan that was set at the manager's discretion to be 30 days long and was highly unreasonable. I made an effort to negotiate the plan and get more time but the manager was not supportive. The environment was quite hostile - micromanaging, nitpicking, unreasonable demands and expectations, which led to a formal HR investigation that paused the plan. The investigation found the claims of inappropriate behaviour to be founded but the plan was reinstated. I am half way through it now after taking some medical leave and if I fail, i am on a PIP. Can I negotiate a mutual separation rather than going through the next 4-5 weeks with these plans?