After changing the property, can the cost be increased while the original contract is still valid?

When the contract comes into effect, the property can't increase the cost at will. If you want to adjust the fee, you must sign a new contract.

Property fees are generally divided into two stages: early property fees and late property fees. The preliminary property fee here generally refers to the preliminary property service contract signed by the developer organization and the property company when the owner closes the house. First, the preliminary property service contract should be terminated when the property company is replaced under normal circumstances, but often this preliminary property service will continue until the community is re-planned. The main reason is that the pre-property service contract is not restricted, and the community owners' committee is usually established because of the intensification of the contradiction between the owners and the property. Neither the property company nor the street office will take the initiative to ask for the establishment of an industry Committee. Without the establishment of the industry Committee, there is basically no possibility of changing the property company in the community. Second, the late property fee is what I specifically mean by distinguishing the early property fee here. It is the property fee charged by re-signing a formal property service contract after the termination of the previous property service contract.