The owners or tenants in common have equal right over the property that they share individually. Tenants in common means two parties are sharing a single property with equal rights. However, the shares may differ. One person may own more than the other in the same property but the rights are not decided based on who owns more or less.
A landlord has the right to change the rent plan as mentioned in the agreement and beyond that they cannot revise. Any landlord has a legal right to increase the rent once a year or every 20 months by a specified percentage that is legally allowed.