Shevuos 1:2-3

Shevuos 1:2

If there was knowledge (of ritual impurity) at the start and at the finish, but a state of unawareness in between, a korban oleh v’yoreid (a variable guilt offering) is brought. If there was knowledge at the start but not at the finish, the goat whose blood is sprinkled in the Kodesh HaKodashim (the Holy of Holies, on Yom Kippur) and Yom Kippur itself suspend punishment until the offender becomes aware, at which time he would bring a korban oleh v’yoreid.

Shevuos 1:3

If there was no knowledge at the start but there was knowledge at the finish, the goat offered on the outer altar (the korban musaf) and Yom Kippur atone for him as per Numbers 29:11, “aside from the sin offering of atonement.” We see from this that both atone for the same types of sin; just as the goat of the inside only atones for a sin of unawareness if the person previously had knowledge, the goat of the outside only atones for sins of unawareness when there was subsequent knowledge.