Can. 902
© Libreria Editrice Vaticana Source: vatican.va
Unless the welfare of the Christian faithful requires or suggests otherwise, priests can concelebrate the Eucharist. They are completely free to celebrate the Eucharist individually, however, but not while a concelebration is taking place in the same church or oratory.
Read the whole title TITLE IIIThe Most Holy Eucharist 897–958