Yes, you have a legal right to collect rent from the use of the duplex. As for selling the property, you can file a lawsuit to partition and force the sale of the property. Here is the California law on court ordered partitions:
Court Action To Partition Real Property
Parties: If real property is owned concurrently or in successive estates, any owner of an estate of inheritance or an estate for life or for years may sue to partition. (C.C.P. 872.210(a)(2).) This provision includes remaindermen but excludes lienholders as potential plaintiffs. Any coowner of personal property may bring a partition action (C.C.P. 872.210(a)(1)), including owners of successive estates (C.C.P. 872.020, 872.710(c)).
Actions by spouses or putative spouses for division of community, quasi-community, or quasi-marital property are expressly excluded from the revised law. (C.C.P. 872.210(b).)
Persons having or claiming interests "in the estate as to which partition is sought" must be joined as defendants if the interest is of record or is actually known to the plaintiff. (C.C.P. 872.510.) "Interests" includes liens, and joinder of additional parties may be necessary under C.C.P. 389. However, holders of interests in oil or gas leases or similar pooling arrangements may be omitted as parties and thus left unaffected by the judgment. (C.C.P. 872.540.)
If partition of all interests is sought, the plaintiff may join "all persons unknown claiming any interest in the property." (C.C.P. 872.550.) Such joinder is required if the name of a defendant is unknown to the plaintiff. (C.C.P. 872.520(a).) If the nature of a defendant's interest is uncertain or contingent, the complaint must so state and must further allege the name, address and legal disability of the owner of any contingent interest insofar as known to the plaintiff. (C.C.P. 872.520(b).) The court must order joinder of additional parties and appoint guardians ad litem as required by C.C.P. 372 et seq. (C.C.P. 872.520(c))
If a person who should be joined is known to be dead, the plaintiff must join the decedent's known personal representative as a defendant. (C.C.P. 872.530(a).) If none is known, defendant must so state in an affidavit and join the decedent's testate and intestate successors and all persons claiming by, through, or under the decedent. (C.C.P. 872.530(b)(1)(2).)
The Complaint: C.C.P. 872.230 specifies the necessary allegations of the complaint:
- A description of the property. Both the legal description and the street address or common designation must be given for real property. For tangible personalty, its usual location must be stated. (See C.C.P. 872.240, permitting partition of real and personal property in one action.)
- The plaintiff's interests as owner and lienholder.
- All interests of record or known to the plaintiff that the plaintiff reasonably believes will be affected by the action. Interests of record in personal property include security interests filed under the Commercial Code.
- The estate to be partitioned and a prayer for partition.
- If a sale of the property is sought, facts justifying the sale.
The complaint must also state the existence and location of any title report procured by the plaintiff (C.C.P. 872.220(a)) and the court may order procurement of a title report by any party (C.C.P. 872.220(b)).
Lis Pendens: Notice of the pendency of an action to partition real property must be recorded by the plaintiff in all counties in which the property is located (C.C.P. 872.250(a)), and a supplemental notice must be recorded for all additional property added to the action (C.C.P. 872.250(b)). If the notice is not recorded, the court must order recordation and stay the action until this is done. (C.C.P. 872.250(c))
Answer: The answer must set forth the interests that the defendant claims in the property, including any liens. (C.C.P. 872.410(a)) Liens must be described by date, character, and amount due. (C.C.P. 872.420.) Additional expenses related to the lien may be alleged, but it is no longer necessary to disclose additional security. The answer must state facts tending to controvert the allegations of the complaint not admitted by the defendant. (C.C.P. 872.410(b).) It may also set forth the defendant's affirmative claims for contribution or other compensatory adjustment. (C.C.P. 872.430) If the defendant seeks a sale, the answer must justify it by allegations of fact. (C.C.P. 872.410(c).)
Trial: Any interest of a party in the property may be put in issue, tried, and determined. (C.C.P. 872.610.) In addition, the court must resolve any other issue necessary to ascertain the state of the title for the purpose of granting relief. (C.C.P. 872.620.) The court must make any necessary determination of the status and priority of liens on the property. (C.C.P. 872.630(a).) A referee may be appointed to take evidence on the issue, ascertain the facts, and report to the court. (C.C.P. 872.630(b).)
Determination By The Court Of Right To Partition
The right to partition depends on the plaintiff's owning a sufficient interest in the property (C.C.P. 872.210) and on the existence of any prerequisites to partition of the particular type of property interests involved.
Partition of concurrent interests is a matter of right unless barred by waiver. (C.C.P. 872.710(b).) Partition of successive estates is allowed only if in the best interest of all parties. In deciding this issue, the court must consider such factors as burdensome expenses, changes in circumstances since creation of the estates, the intent of the creator, and the needs and interests of the successive owners. (C.C.P. 872.710(c).)
Partition of partnership property may be permitted if rights of unsecured partnership creditors will not be prejudiced; alternatively, the partition procedure may be applied in a partnership accounting and dissolution proceeding. (C.C.P. 872.730.)
Determination By The Court Of The Manner Of Partition
Partition is by physical division unless the parties agree on a sale or the court determines that partition by sale would be "more equitable." (C.C.P. 872.810, 872.820.).
The court may order part of the property partitioned by sale and the remainder by physical division. (C.C.P. 872.830.)
The court may appoint a referee to assist its determination whether to order a physical division or a sale. (C.C.P. 872.820(b).)
Partition of property subject to an express trust may be by sale simply in the court's discretion. (C.C.P. 872.840(a).)
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