Illegal. It is illegal to change a product name without permission. It is illegal to relabel products. Infringes upon the exclusive rights of registered trademarks of others. Legal basis: Article 140 of the Product Quality Law: Producers and sellers adulterate or adulterate products, pass off fake products as genuine products, pass off substandard products as good products, or pass off unqualified products as qualified products, and the sales amount is 50,000 yuan. If the amount exceeds 200,000 yuan, he shall be sentenced to fixed-term imprisonment of not more than two years or criminal detention.