Can I petition the court for a partition order without an attorney?

Yes, an individual can act as their own attorney. However, Partition actions are very technical different rules than regular civil actions. You must purchase a litigation guarantee from a title company, and file a copy of the litigation guaranty with the complaint to partition. Your complaint needs to name as defendants, all persons identified in the Litigation Guarantee, as having a potential interest in the property, as well as all unknown persons claiming any such interest. You then need to get a court order permitting service of the unknown persons by publishing the Summons in an appropriate newspaper. You also need to get a court order permitting you to record a Lis Pendens, and file a copy of the Lis Pendens with the County Recorder's stamp in the court file. Partition is governed generally by Code Civ. Proc. 872.010 et seq. and 874.010 et seq.The procedure for partition by sale is governed by Code Civ. Proc. 873.510 et seq. The procedure for partition by appraisal is governed by Code Civ. Proc. 873.910 et seq.

You don't have to have an attorney but partition is a time consuming effort. If at all possible, one party should buy out the other or create an arrangement whereby the party staying pays rent to the person that leaves. Either that or a sale to a third party.

While you are entitled to represent yourself in most matters, it is not advisable to do so in complicated matters such as partition. Co-ownership does not mean that both of you must occupy the property. You should consult a real estate attorney to see if something short of partition would work for the two of you.

You can; it may not be done right and it may take a lot longer than it should with a good real estate attorney, but sure, you can do it.

Yes you may file a partition suit without an attorney.. however it will be much easier with one (but more expensive)Also please take note that if you own the house with your sister as joint tenants with right of survivorship you have no right to partition it and your petition will be rejected.