Tractate Yevamot - Chapter 13 - Mishnah 1 יבמות פרק י״ג משנה א׳

Beth Shammai says: Only those who are betrothed may exercise the right of refusal; But Beth hillel says: Both those who are betrothed and those who are married. Beth Shammai says: [A declaration of refusal may be made] against a husband but not against a yavam; But Beth Hillel says: Either against a husband or against a yavam. Beth Shammai says: [The declaration] must be made in his presence, But Beth Hillel says: Either in his presence or not in his presence. Beth Shammai says: [The declaration must be made] before the court, But Beth Hillel says: Either before the court or not before the court. Beth Hillel said to Beth Shammai: [A girl] may exercise the right of refusal while she is a minor even four or five times. Beth Shammai said to them: “The daughters of Israel are not ownerless property! Rather, either she makes a declaration of refusal and then waits until she is of age, or she makes a declaration of refusal and marries again [immediately]. Section one: According to Beth Shammai only those who are betrothed are allowed to make a declaration of refusal and thereby leave their husbands without a get. Beth Hillel says even if she was married she may do so. According to the Talmud, Beth Shammai allows only the betrothed woman to refuse because if the married woman also was able to refuse, men would not want to spend the money involved in marrying a minor, lest she later refuse the marriage. Section two: If the minor girl was married off by her mother or brother and then her husband died, according to Beth Shammai she cannot make a declaration against her yavam. Rather she must wait until she reaches majority age and then request halitzah. However, according to Beth Hillel she may make such a declaration against the yavam as well. However, even though she has annulled her marriage to the yavam’s brother, she cannot at a later point marry the yavam, since she was at one point his brother’s wife. Section three: According to Beth Shammai, she must make the declaration of refusal in front of him. According to Beth Hillel, this is not necessary. Section four: According to Beth Shammai, she must make the declaration of refusal in front of a court. According to Beth Hillel, this is not necessary. Section five: According to Beth Hillel, as long as she is still a minor, she may be married off as many times as her brothers and mother wish and she may later refuse as many marriages as they offer. Beth Shammai offers a moral objection to this possibility, for through it a girl could be betrothed (but according to Beth Shammai not married) to several men without ever having received a get. Rather she either waits until she is an adult or makes a declaration of refusal and then marries immediately, at which point she could no longer refuse, according to Beth Shammai. Note that this last section is phrased differently than the previous sections. According to some mishnaic commentators, since Beth Shammai explains their position the halakhah is according to them in this section. In all of the other sections, the halakhah follows Beth Hillel, as it usually does.