Temurah 5:3

If a person said that the offspring of a pregnant animal should be a burnt offering and the mother animal should be a peace offering, his statement is upheld. If he said that the mother should be a peace offering and its offspring a burnt offering, Rabbi Meir says it is the offspring of a peace offering (and its status cannot be changed). Rabbi Yosi says that if this was his original intention, his words are upheld because a person can’t say both things simultaneously. However, if he only decided to declare the offspring a burnt offering after declaring the mother a peace offering, then it is the offspring of a peace offering.

Temurah 5:4

If a person said that a certain animal should be the temurah of a burnt offering and the temurah of a peace offering, Rabbi Meir says that it’s the temurah of a burnt offering. Rabbi Yosi says that if this was his original intention, his words are upheld (with the result that the animal must be left to graze until it develops a blemish), again because a person can’t state both things simultaneously. However, if he only decided to declare it the temurah a peace offering after declaring it the temurah of a burnt offering, then it is the temurah of a burnt offering.