If you want to adjust the price of a plan variant or a component already booked by customers, the price changes, both for existing customers and for new customers of the plan variant and component.
If you want to keep the prices for existing customers, it is recommended to create a new plan variant / component with the new price for new customers and keep the old plan variant / component for existing customers. Existing customers can then be rebooked into the new plan variant or component step by step, using the up/downgrade function within the user interface or via REST API.
If the price of an existing plan variant or component is adjusted, the new price for an existing customer with a contract will be applied to the next regular billing. If you make changes to the contract in a period that has already been billed (e.g. upgrades/downgrades or changes to component or discount bookings) or make retroactive changes that include the period before the price change, the current valid price is always used for these calculations.
How you can create new package variants is explained here.