I want to take this in two pieces. The first, the question of values and morals; the second, the question of repercussions.
It is true that the yammim noraim, the Days of Awe (that is to say, the High Holidays) have a particular pull on the Jewish conscience. Even those who do not normally affiliate or find time to worship on a daily or weekly basis, or celebrate any other festival in the synagogue, try to find a way to observe these. Perhaps it is because they are uniquely focused on synagogue (as opposed to other holidays, like Sukkot, Pesach and Shabbat, which are more oriented toward home practice). Perhaps it is a sense that, at the beginning of Autumn, we have a need for Cheshbon Hanefesh, the accounting of the soul that takes place at this time. Perhaps it’s merely a form of “Jewish Behaviorism”—i.e. I do this because my bubbe and zayde do it. Regardless, the yammim noraim are profoundly important to the Jewish Soul, and every effort should be made to observe the holidays—to hear the sound of the shofar, study the relevant texts, and fast and perform teshuvah (repentance) on Yom Kippur. Of course, with our global economy and 24/7 demands on people’s lives, sometimes we cannot observe as we would prefer. Nevertheless, if someone is kept away from the holidays due to travel or the like, they should try to seek out a synagogue or congregation in the city they’re visiting, even if it means gathering a small minyan together. Increasingly, many congregations live stream their services, and perhaps the individual could ‘tune in’ that way. While the individual won’t count as part of the minyan, she would be able to follow along and participate in some manner. If full worship is not possible, then the individual should carve some time out for personal prayer and reflection. If the individual knows in advance that she will not be able to attend the holidays, then perhaps she could endeavor to study in advance, such as Sefer HaHinuch or the Trials of Abraham, or participate in pre-High Holiday rituals such as Selichot.
(Please note that, as a Reform Jew, I assume a “Jewish Lady” is a full member of the minyan and able to participate meaningfully, as opposed to being somehow excluded based on gender. Likewise I assume the individual is not incapacitated due to illness; of course, in such a circumstance, there is no obligation to do anything other than heal).
Now, let’s talk about ‘repercussions’. I’m not sure what that would mean beyond one’s own conscience, and perhaps her engagement with the rest of her faith community. Certainly one’s spiritual health is as important as one’s physical and psychological health, and so these important days should not be ignored; we need that time to reflect on our past year and explore what it would mean for us to do better, to be better, to live up to our own best selves. While fear of someone ‘keeping score’ or the absence from shul somehow ‘going on one’s permanent record’ might be a helpful motivator for some, if that isn’t possible, the question then becomes one of teshuvah and how she might earn forgiveness from herself for ignoring her spiritual needs? To that end, she might consider a more careful observance of Rosh Hodesh. There are traditions in Judaism that treat The New Moon as a time of reflection, renewal and repentance; treating each as a ‘mini Yom Kippur’ might be a helpful way for her to feel that she has engaged in meaningful, spiritual self-care. Regardless, she should be mindful of the words of Kol Nidre: while we make promises and vows throughout the year, sometimes we are unable to keep them. For those sins of omission, of good intentions gone wrong, may we all be forgiven.