White tie is the most formal evening costume code. It is worn to events such as balls, the opus, and formal dinners. The chief mechanism for men are the dress coat, white bow tie and waistcoat, and starched shirt, while women wear a suitable dress for the occasion, such as a ball gown.White tie is worn only to events after six o'clock and before that time the daytime equivalent called morning dress is worn. The semi-formal counterpart of white tie are black tie in the evening and, rarely worn, semi-formal morning dress during the day, a code in between an informal lounge suit and full morning dress. The dress coat worn with white tie is a descendent of the coat worn at all times of day in the Regency period, so is also part of other related codes, such as civilian day court dress in the Royal court . However, these alternatives are now being replaced by standard white tie for formal state occasions, such as for ambassadors at the State Opening of Parliament.