The motion to impeach is used to bring an accusation against a person.
A majority vote is needed to put the accused on trial.
[1] A majority vote convicts for a minor offense, and a two-thirds vote for a major offense.
[2] Robert's Rules of Order does not have a motion to impeach.
However, this book requires a fair disciplinary process which includes appointing a committee to conduct a confidential investigation, report of the committee and preferral of charges if warranted, formal notification of the accused, and trial;[3] and a two-thirds vote is required to expel.