Reference for Ketubot 174:9

איבעיא להו פוחתת כתובתה מהו מי אמרינן היינו פוגמת או דלמא פוגמת מודיא במקצת הא לא קא מודיא במקצת

The question was raised: What if a woman declares her [original] ketubah to have been less [than the amount recorded in the document]? Do we say that such a woman is in the same position as the woman who impaired [her ketubah] or is it possible that the woman who impairs [her ketubah] admits a part [of the full sum] while this one does not admit a part [of the full sum]?

Jastrow