I would just stand up at the next chapter meeting and speak from your heart. Tell your sisters that you realize you were not giving as much time to your office as you should have, and you do understand their decision (because it sounds like you do) and assure them that you still want to give as much time as you can. It sounds like the last girl this happened to took it too personally...sometimes it has NOTHING to do with that. It takes a lot more guts and caring to admit you are overextended and take some things off your plate, then it does to keep muddling through because you are too proud to admit it. Good luck.