Hello, my name is***** am a qualified lawyer and I will be assisting you with your question today. If someone has resigned then this would be official reason for their termination as and as they are not going to be made redundant they will not be entitled to any redundancy payment. You can basically remove them from the redundancy procedure and not consider them for redundancy any more. If you want them to work past the end of their notice period then what you could do is just mutually agree to extend her notice period to cover the additional time you want them to work for you. Their employment would still end after that period by reason of resignation. However, if she refuses to extend her notice period you cannot force her to continue working past the end f her notice period. So this is only possible if she has agreed to the extension.
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