Under extenuating circumstances, women may make a “condition” by saying “I am lighting Shabbat candles but not starting Shabbat until sunset” to delay Shabbat until sunset, when it will begin anyway.
NoteWomen should not routinely start Shabbat at sunset since the proper time for women to begin Shabbat is at candle lighting (typically 18 minutes before sunset).
ReasonAn opinion exists that Shabbat actually begins at 18 minutes before sunset; that is the origin of this time for women to begin Shabbat.