A Eucharistic Minister (also known as an Extraordinary Minister of Holy Communion) is a lay person who is commissioned to assist the Priest in the distribution of Holy Communion – the consecrated bread and wine. They may also take Communion to those who are ill in hospital and/or otherwise unable to attend Mass.
This person should regard what they do as ministry to their brothers and sisters. It follows therefore that you are prepared beforehand, and if you foresee that you cannot honour your rota, please make yourself absent ASAP and ask somebody else to stand in for you.