Any given manuscript of the New Testament will vary from the standard text in certain places. Even minor variations, which may have little or no significance for the meaning of the text, can help place a particular manuscript in a sort of "Family Tree" of the New Testament. Using this tree, scholars can reconstruct the history and evolution of the text. In most modern editions of the Greek New Testament, textual variants are printed at the bottom of the page and marked by critical signs in the text for easy reference.
P46, like any manuscript of its age, contains an abundance of variant readings. Below are three examples which come from Galatians 1.1-1.5, the segment of the papyrus which is featured in this exhibit.
Galatians 1.3 - In P46, the word order of ἡμῶν καὶ κυρίου is altered, giving καὶ κυρίου ἡμῶν instead. This has only a slight effect on the meaning of the phrase, and is not significant in terms of theology. However, because the same word order of P46 is found in several other manuscripts, this helps establish the place of P46 in the manuscript tradition.
χάρις ὑμῖν καὶ εἰρήνη ἀπὸ θεοῦ πατρὸς ἡμῶν καὶ κυρίου Ἰησοῦ Χριστοῦ
Greetings to you and peace from God our Father and the Lord Jesus Christ
χάρις ὑμεῖν καὶ εἰρήνη ἀπὸ θεοῦ πατρὸς καὶ κυρίου ἡμῶν Ἰησοῦ Χριστοῦ
Greetings to you and peace from God the Father and our Lord Jesus Christ
Galatians 1.4 - Here, P46 substitutes the preposition περί in the place where the standard text uses ὑπέρ. In fact, ὑπέρ and περί are frequently interchanged in the manuscripts, and the change in meaning is not significant (both are used in a phrase meaning, basically, "for our sins"). More important is the relationship between different manuscripts showing the variant reading.
τοῦ δόντος αὑτὸν ὑπὲρ τῶν ἁμαρτιῶν ἡμῶν,
... who gave himself for the sake of our sins,
τοῦ δόντος αὑτὸν περὶ τῶν ἁμαρτιῶν ἡμῶν,
... who gave himself to atone for our sins,
Galatians 1.4 - Here is an example where a variant reading exists in other texts, but the standard text follow the same tradition as P46. The effect of the change in word order is difficult to capture in English, though the Greek of the variant reading is somwhat garbled (and this is why the standard reading is preferred by editors).
P46 & the Standard Text:
ἐκ τοῦ αἰῶνος τοῦ ἐνεστῶτος πονηροῦ
... from the present evil age
ἐκ τοῦ ἐνεστῶτος τοῦ αἰῶνος πονηροῦ
... from the present age of evil
As these cases show, variant readings are quite common but not often very exciting. While it is rare to find a variant reading that would alter the tenets of Christianity, taken together these variants help scholars establish a clearer understanding of the intentions of the New Testament authors, and their work is reflected in the current editions and translations of the New Testament.
 W. Bauer, Greek-English Lexicon of the New Testament and Other Early Christian Literature, Second Edition (Chicago 1979) s.v. ὑπέρ, f.