If a woman already davened Maariv but she forgot that she davened and then later on began davening the shemone esrei of Maariv again and reminded herself in the middle of the bracha, what is the correct thing to do? Continue davening, stop in the middle of the bracha?
A person that already davened, and remembers in middle of shemona esrei, stops right in middle of the bracha. The reason is because tefilos are like bringing a korban, and he already brought this korban. On the other hand, even though there is an idea of davening a tefilas nedava, that is only if the whole shmona esrei will be nedava. However we can not bring a korban that is partially obligatory and partially nedava. This applies even for women in instances that they don’t have an obligation to daven, and even by maariv. the reason being is that this tefillah was not being said with the intent of being nedava with its halachos, (concentrating on every word, and adding to the tefilah) rather as obligatory.
O”CH 107-1 Mishna Berura ibid.-7, Tehilah L’dovid ibid.-1, Orach Neeman ibid-8 regarding women.