You have the right to have personal data about you corrected if it is inaccurate or incomplete.
The organisation must act within one month, but the deadline can be extended by two months if the request is complex.
Either the data must be corrected, or the organisation must explain to you why it cannot. It must also remind you of your right to complain to the supervisory authority and to a court.
Sometimes it may not be possible to correct data, for example, if the data is complicated and stored in a way where change is expensive or impractical. Sometimes, the organisation might not agree with you that the data is incorrect, and therefore has no obligation to change it.
If the data has been given to anyone else, the organisation must also inform them to make the corrections, and inform you that it has done so. However, it is not liable for making sure that the other organisation acts correctly.