Reference for Avodah Zarah 128:15

ובעובד כוכבים עד שישכור כיצד אומר לו רשותי קנויה לך רשותי מבוטלת לך קנה ואין צריך לזכות

whereas a non-Jew can do this only by renting [his property]. How so? [One Jew] can say to [another Jew], “My ownership is acquired by you; my ownership is renounced in your favor” and the latter has thereby acquired [the property] without the necessity of a formal assignment.

Jastrow