This right provided for in Article 16 of the GDPR allows the data subject to obtain from the data controller, as soon as possible, the rectification of personal data concerning him or her which is inaccurate.
Given the purposes of the processing, this may involve a correction in the event of inaccuracy (an address, a date of birth, etc.), an update of data, or completion of existing data, including by providing an additional declaration.
This right of rectification is excluded for certain types of processing, such as literary, artistic and journalistic processing.
With regard to police, gendarmerie and intelligence files (more generally relating to state security), the right of rectification can be exercised indirectly via the data protection authority (such as the CNIL in France).
In addition to this obligation on the part of the data controller, there is also the obligation to inform the recipients of the data of the change(s) that have been made, except where this is impossible or would require disproportionate effort (Article 19 of the GDPR).