Employee Grievance Letter – How to write a grievance letter to your employer. Before your lodge your grievance letter to enter the grievance procedure, give yourself a quick lesson in employment law to know your employment rights. As of April 6 th 2014, you cannot lodge a claim in the Employment Tribunal until ACAS has been given a chance to conciliate between you and your employer to attempt to obviate the litigative route. Thus, I cannot understate the importance of getting your grievance letter right. Spending an hour or so reading through the pages of will help you to accomplish this. In turn, this will provide you with a fighting chance against both your employer, and their solicitors.