According to the relevant laws and regulations of our country, it is not illegal to change the office building. In business activities, enterprises or individuals have the right to choose suitable business premises, including choosing to use office buildings as office locations. Changing the office building is a part of the enterprise's independent decision. As long as it is operated in accordance with the law and the contract, it is a legal and common business behavior.

However, changing office buildings may involve some relevant regulations and procedures. If you are considering changing office buildings, I suggest you pay attention to the following points:

1. Contract performance: If you have signed a lease contract with a training institution before, you need to read the terms of the contract carefully to understand the terms of breach of contract and early termination of the contract. If there is a risk of default, you need to discuss the solution with the training institution.

2. Administrative examination and approval: Before choosing a new office building, you need to know the regulations of the local government and whether it is necessary to conduct administrative examination and approval or go through relevant procedures. Some places may have specific requirements for the use of office buildings.

3. Cost consideration: Although choosing to change the office building may reduce the cost, it is still necessary to weigh the rent, location, transportation convenience and surrounding facilities of the old and new office buildings. Sometimes, moving to a new office building will bring additional decoration, relocation and operating costs.

Generally speaking, it is legal to replace the office building, but in the process of operation, we should understand the relevant laws, regulations and contractual agreements and consider various factors to achieve the best commercial interests. If specific questions need more detailed answers, it is recommended to consult relevant legal professionals.