Pesachim8: 8
אוֹנֵן טוֹבֵל וְאוֹכֵל אֶת פִּסְחוֹ לָעֶרֶב, אֲבָל לֹא בַקָּדָשִׁים.  הַשּׁוֹמֵעַ עַל מֵתוֹ, וְהַמְלַקֵּט לוֹ עֲצָמוֹת, טוֹבֵל וְאוֹכֵל בַּקָּדָשִׁים.  גֵּר שֶׁנִּתְגַּיֵּר בְּעֶרֶב פֶּסַח — בֵּית שַׁמַּאי אוֹמְרִים: טוֹבֵל וְאוֹכֵל אֶת פִּסְחוֹ לָעֶרֶב.  וּבֵית הִלֵּל אוֹמְרִים: הַפּוֹרֵשׁ מִן הָעָרְלָה כְּפוֹרֵשׁ מִן הַקֶּבֶר.
An onain immerses [himself] and eats his pesach-offering in the evening, but [may] not [eat other] offerings.  One who hears about the death of his relative, or one who has arranged for bones [of a close relative] to be gathered on his behalf, immerses [himself] and eats of offerings.  [If] a proselyte had been converted on the eve of Pesach —- Beis Shammai say he immerses [himself] and eats of his pesach-offering in the evening.  But Beis Hillel say: One who separates [himself] from an uncircumcised state is like one who separates himself from the grave.