בְּע֣וֹד ׀ שְׁלֹ֣שֶׁת יָמִ֗ים יִשָּׂ֤א פַרְעֹה֙ אֶת־רֹאשֶׁ֔ךָ וַהֲשִֽׁיבְךָ֖ עַל־כַּנֶּ֑ךָ וְנָתַתָּ֤ כוֹס־פַּרְעֹה֙ בְּיָד֔וֹ כַּמִּשְׁפָּט֙ הָֽרִאשׁ֔וֹן אֲשֶׁ֥ר הָיִ֖יתָ מַשְׁקֵֽהוּ׃
within yet three days shall Pharaoh lift up thy head, and restore thee unto thine office; and thou shalt give Pharaoh’s cup into his hand, after the former manner when thou wast his butler.
Rashi on Genesis
ישא פרעה את ראשך PHARAOH SHALL LIFT UP THY HEAD — The words נשא ראש denote to count (cf. Exodus 30:12). When he musters his other servants to wait upon him during the meal he will count you also among them.
Rashbam on Genesis
ישא פרעה את ראשך, the use of the word ישא here is similar to the use of the same word in Numbers 1,2 שאו את ראש כל עדת ישראל, “count the whole community of Israel, etc.” After three days Pharaoh will again number you among his servants.
Sforno on Genesis
As was your previous practice. Before you became an official.