Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Canons of the Councils of Ancyra, Gangra, Neocæsarea, Antioch and Laodicea, which Canons were Accepted and Received by the Ecumenical Synods.: Canon XVI

Canon XVI.

If any bishop without a see shall throw himself upon a vacant church and seize its throne, without a full synod, he shall be cast out, even if all the people over whom he has usurped jurisdiction should choose him.  And that shall be [accounted] a full synod, in which the metropolitan is present.

Notes.

Ancient Epitome of Canon XVI.

Whoever without the full synod and without the Metropolitan Council, shall go over to a vacant church, even if he has no position, he shall be ejected.

Beveridge.

This, together with the following canon, was recited by Bishop Leontius in the Council of Chalcedon, from the book of the canons, in which this is called the 95th and the following the 96th, according to the order observed in that book of the canons.

This canon is found in the Corpus Juris Canonici, Gratian’s Decretum, Pars I., Dist. XCII., Can. viij. in Isidore’s version, and the Roman Correctors note its departure from the original.