Broomstick, so sorry I had not seen your previous post.
Here in Switzerland, people can subscribe to a Society called EXIT and become a member (Swiss or foreign, but have to be resident here)- and then, after being a member for about 6 months, can ask EXIT for assistance. A trained volunteer would then visit, and interview you, alone, to ensure this is REALLY what you want, and that no pressure is born to bear by relatives, etc. If the volunteer is totally satisfied- then a date is made- and plans for where and how. In bed, in the lounge- the garden even if private- music, family or a friend present, pets- etc, etc- and a date made. On the day, the volunteer will again interview the person alone, to ensure above, again, and make preparations- and then will give the potion to the member to take themselves. The volunteer will wait for death, which is instantaneous, then call the police and the doctor- who will confirm death. The procedure is filmed, just in case, but the film not kept once police releases the body for burial or cremation, etc.
Members are advised to make their wishes known to their doctor and solicitor, who may be consulted, but this is not necessary.