Zevachim page 7 Tosphot. Rambam invalid sacrifies chapter 15, law 8.

There is an argument between Tosphot and the Rambam. To Tosphot if one slaughters a burnt offering for someone who is not obligated in brining a burnt offering, then that burnt offering is valid and fulfills the obligation of the person that vowed to bring it. The reason is that the case of the burnt offering is parallel to that case of the sin offering in that if one slaughters a sin offering for the sake of someone who is not obligated in a sin offering then that sin offering is valid, but does not fulfill the obligation of the person that was required to bring it and sanctified that animal. However, the Rambam accepts this reasoning to some degree, but instead claims that everyone some point transgressed a positive command. Therefore, if one slaughters a burnt offering for the sake of someone else who is not obligated in burnt offering, we still say that this is a change of the owner, and therefore even though it is valid, it does not fulfill the obligation of the one who is obligated to bring the burnt offering, and who vowed this particular animal. The question I have on this Rambam is that even if in theory, everyone is obligated in a burnt offering for neglect of a positive command, that is not the same thing as actually vowing to bring a burnt offering. In the case of a sin offering also, for there to be considered a change of owners, the other person must have not only eaten forbidden fat, but to have in fact been obligated in bringing a sin offering because he knows he did so.----The basic idea here is that a sin offering is different in a significant way from a burnt offering in that a burnt offering that is sacrificed for the sake of another kind of sacrifice of for another person, that burnt offering is valid but does not fulfill the obligation of the one who vowed it. But a sin offering in the same circumstance is not valid at all. But there is a exception in the case of the sin offering in that if one slaughters it for someone who is obligated in a burnt offering or for as if it is not a sacrifice at all, it is valid but does not fulfill the obligation. the foundational principle here is that for a change in the person for who the animal was sacrificed the other person needs also to be obligated in a sin offering. A same type can damage the same type. A different type cannot detract from it. ==============================There is an argument between תוספות and the רמב’’ם. To תוספות if one slaughters a עולה for someone who is not obligated in brining a עולה, then that עולה is valid and fulfills the obligation of the person that vowed to bring it. The reason is that the case of the עולה is parallel to that case of the חטאת in that if one slaughters a חטאת for the sake of someone who is not obligated in a חטאת then that חטאת is valid, but does not fulfill the obligation of the person that was required to bring it and sanctified that animal. However, the רמב’’ם accepts this reasoning to some degree, but instead claims that everyone some point transgressed a positive command. Therefore, if one slaughters a עולה for the sake of someone else who is not obligated in עולה, we still say that this is a שינוי בעלים and therefore even though it is valid, it does not fulfill the obligation of the one who is obligated to bring the עולה, and who vowed this particular animal. The question I have on this רמב’’ם is that even if in theory, everyone is obligated in a עולה for neglect of a positive command, that is not the same thing as actually vowing to bring a עולה. In the case of a חטאת also, for there to be considered a שינוי בעלים, the other person must have not only eaten forbidden fat חלב , but to have in fact been obligated in bringing a חטאת because he knows he did so.----The basic idea here is that a חטאת is different in a significant way from a עולה in that a עולה that is sacrificed for the sake of another kind of sacrifice OR for another person, that עולה is valid but does not fulfill the obligation of the one who vowed it. But a חטאת in the same circumstance is not valid at all. But there is a exception in the case of the חטאת in that if one slaughters it for someone who is obligated in a עולה or for as if it is not a sacrifice at all, it is valid, but does not fulfill the obligation. The foundational principle here is that for a שינוי בעלים ,the other person needs also to be obligated in a חטאת. A same type can detract from the same type. A different type cannot detract from it.