Yevamos5: 2
כֵּיצַד? עָשָׂה מַאֲמָר בִּיבִמְתּוֹ, וְנָתַן לָהּ גֵּט — צְרִיכָה הֵימֶנּוּ חֲלִיצָה. עָשָׂה מַאֲמָר וַחֲלִיצָה — צְרִיכָה הֵימֶנּוּ גֵּט. עָשָׂה מַאֲמָר וּבָעַל — הֲרֵי זוֹ כְּמִצְוָתָהּ.
How so? [If] he performed maamar with his yevamah and then gave her a bill of divorce, she requires chalitzah from him. [If] he performed maamar [with her] and then chalitzah, she requires a bill of divorce from him. [If] he performed maamar and then cohabited [with her], he has done it properly.