Pesahim 92a and Pesahim 92b, finishing a chapter with issues of when Hazal kept their rules in place even if it meant not offering the Pesah, and when they did not, and then starting on the chapter about Pesah Sheni, when people can or cannot offer the first Pesah and are delayed to the second, starting with whether someone far away can have a messenger offer the Pesah on his/her behalf, and then s/he eat it that night.
