Perhaps go to another medical establishment? Get a second opinion.
To my knowledge, as an RN, you cannot "change" notes! What the nurse or provider writes MUST stay in the record. For them to change anything in a medical record they must add an addendum! This is why there is NO PENCIL documentation allowed. It's also why WHITE OUT is not allowed in the medical record. Too many people have been caught falsifying documentation in the medical record, and that is why when medical personal hand write notes, they must NOT skip any lines from the last documentation present. And, at the end of their note, if it doesn't fill up the line, they must initial it, put their title, and then draw a line from that to the end of that line. All they will be able to do in your case is write or type an addendum to the note, stating that you have provided a "correct" diagnosis to them. Chances are good however that it won't happen since it could open them up to a misdiagnosis (malpractice) lawsuit, if you suffered permanent damage or injury due to the misdiagnosis!
I agree with CP3kids.
Your notes cannot be changed or altered, but if you do have medical evidence to support what you say (like a letter from another consultant or specialist or your doctor) you can send a copy of that with a letter to the hospital that treated you. Send it to their records department.
In any event, being treated at your hospital you will have a National Health Service number and also a Hospital Number that will be on all your records. Any consultations no matter when these were at that hospital will be kept on your file at that hospital.
When you go to the accident and emergency, they assess your condition and write down what they find at that time. Even if they do get it wrong, those notes stay on your records, but new information can be added.
If you feel that you did not get the correct treatment at the hospital or have any complaints, you can also write a letter to the hospital's manager. You can find information on the web with regard to information on the hospital you attended, or you can telephone the hospital and ask them to give you the details and the name of the person and their position, to address your letter to and the department that it should be sent to.
When you write your letter and send copies (keep any originals) of any supporting evidence, at the end of your letter give the hospital a set amount of time to respond to you. Most hospitals have a policy to at least acknowledge your letter after a specific time. If you do not hear anything after a few weeks, chase it up, by requesting a response. Don't forget to write your National Health Service or Hospital Number on all correspondence.
Should the misdiagnosis have led to negligence, it would be better not to get your records updated just yet, but to seek advice from the Citizens Advice Bureau (you can find their information for the one in your area on the web or in the phone book)