When saying Amen, a person should make sure not to say it too quickly. A person should wait until the blessing is completed before beginning to say Amen. This is true even if the Chazzan extends the last part of the blessing. For example, on Rosh Chodesh, it is common to extend the last word in Shemone Esray (B’Shalom). The congregants should make sure the entire word is completed before responding Amen.