Partition can not be done without court action. Given all the questions you have posted I suggest you go pay for a consultation with a real estate lawyer. I thinkit give you piece of mind.
I am a former federal and State prosecutor and have been handling criminal defense and personal injury cases for over 17 years. The above answer, and any follow up comments or emails, is for informational purposes only and not meant as legal advice.
Your partial owner rights in the home derived from a deed may end by a negotiated agreement where you are paid the fair value of the interest you own in the home in exchange for a new deed delivered to your sister and parents, or by a court making an award in a lawsuit started by the other owners against you if you cannot come to an agreement. It is not likely that a court becomes involved unless all reasonable attempts with attorneys representing all owners does not lead to a settlement.
I sense you made the same or similar inquiry from a number of different directions, but the bottom line is your ownership interest can end with your written agreement and money paid to you for the value of your interest (you too have the right to buy out the rights of the co-owners) and a new deed, and if with all the effort of lawyers to make a deal fail by a judge.
The answer provided to you is in the nature of general information. The general proposition being that you should try to avoid a bad outcome if you can.