I am a lay Eucharistic minister and every once in a while I am asked to expose the Eucharist in the monstrance, and other times I am asked to repose at the end of adoration hours. I do it with utmost respect and follow the normal prayers that the priest or deacon would use. I would never do it without a recent confession and in a state of grace. But I always feel a little funny about it. Is it OK if I do this or should this be done by a deacon or priest? .
If a deacon or priest is not present then an EMHC may expose and repose the Blessed Sacrament.
Can. 943 The minister of exposition of the Most Blessed Sacrament and of eucharistic benediction is a priest or deacon; in special circumstances, the minister of exposition and reposition alone without benediction is the acolyte, extraordinary minister of holy communion, or someone else designated by the local ordinary; the prescripts of the diocesan bishop are to be observed.
However, given that the canon states that a lay minister may only expose and repose, I would not think its appropriate for you to lead the prayers that a priest or deacon would normally say. I would recommend only exposing and reposing the Blessed Sacrament in a simple manner.