Complex sentence: During the notice period, the employer could make the employee redundant or summarily dismiss them, if it has the grounds to do so fairly, otherwise the reason for termination will be resignation and not dismissal, since the employee cannot serve a counternotice.
Split into simpler sentences: During the notice period, the employer could make the employee redundant or summarily dismiss them, if it has the grounds to do so fairly. Otherwise, the reason for termination will be resignation and not dismissal, since the employee cannot serve a counternotice.