Zevachim 34 - Service Interruptions That Can Be Fixed
We have learned that persons disqualified for services are allowed to do the act of slaughtering the sacrifice. However, if they have continued and received the blood, then the law is as follows: if there is some lifeblood spurting from the neck of the animal, a qualified person should receive the blood and complete the service.
If a qualified person received the blood and handed it to a disqualified person, the latter should simply return the blood, and the service continues. If the kohen received the blood with his right hand, but then put the vessel in his left hand - he should return it to his right hand and continue. If the blood spilled on the floor and he gathered it - it is valid.
Resh Lakish asked Rabbi Yochanan, "What if the disqualified person not only received the blood, but also threw it on the Altar, can this be corrected?" Rabbi Yochanan answered, "Yes. Unless he intended to eat it in the wrong place or beyond the right time, because then it became rejected."
Art: Diego Rodriguez de Silva y Velazquez - Joseph's Bloody Coat Brought to Jacob