Berachos 13a (continuation of the name change).
לא יקרא שמך עוד יעקב — לא שיעקר שם יעקב, אלא שיהיה ישראל עיקר ויעקב טפל לו.
“Your name shall no longer be called Yaakov” — not that the name Yaakov is uprooted, but that Yisrael shall be primary and Yaakov secondary to it.
Yisrael becomes the primary name; Yaakov remains but is secondary.