On Holy Thursday morning (in some dioceses it may be another morning during Holy Week), the bishop, joined by the priests of the diocese, gather at the Cathedral to celebrate the Chrism Mass. This Mass manifests the unity of the priests with their bishop.
Here the bishop blesses three oils — the oil of catechumens (oleum catechumenorum or oleum sanctorum), the oil of the infirm (oleum infirmorum) and holy chrism (sacrum chrisma) — which will be used in the administration of the sacraments throughout the diocese for the year. This tradition is rooted in the early Church as noted in the Gelasian Sacramentary (named after Pope Gelasius I, d. 496), but was later absorbed into the Holy Thursday evening Mass; Pope Pius XII issued a new Ordinal for Holy Week, which reinstituted a special Mass of the chrism distinct from the evening Mass.
There is nothing that I can find on the Diocesan website, but priests are also renewing their vows at the Mass.