To correct or fix something that is wrong or has gone wrong.
“I want to rectify this mistake as soon as possible.”
“To rectify the error, I've arranged a replacement for tomorrow morning.”
This more formal verb works well in Task 6 when you're proposing to fix a mistake, especially your own, since it sounds sincere and responsible. For example, 'I'd like to rectify the situation by covering the extra cost' shows accountability, which raters respond well to.
Synonyms: correct, fix, remedy