Any change to a product, including product descriptions and packaging may require a new GTIN please use the Decision Support Tool to help you decide if a new GTIN is required.
If you have any questions please email email@example.com
The principles are that the brand owner is responsible for allocating GTINs and each variant of a product must be identified with its own unique GTIN.
The complete Rules may be found at
Also see article 'Can I re-use a GTIN (Barcode number)?'.