We learn in Parshas Masei about a person who unintentionally murders another.
The halacha is that the unintentional murderer is to flee to one of the Arei Miklat (Cities of Refuge), and stay there until the current Kohen Gadol passes away. If the unintentional murderer leaves the Ir Miklat, the Go'el Hadam (avenger of blood) is permitted to kill the Rotze'ach (murderer), and will be patur (exempt) from judgment. (See Bamidbar 35:21-28.)
Since the Rotze'ach is not allowed to leave the Ir Miklat until the Kohen Gadol's death, what does he do during the Shalosh Regalim, when it is obligatory that every Jewish man aged 13 and older appear in Jerusalem to present a korban?