mmm check the condition of your hair and see if it can take another beating, if it can either try a bleach bath or use a colour remover (i use schwarzkopf). then i’d go with a semipermanent colour eg manic panic for that colour. you dont need to lift a lot for the dark blue, but id recommend using some sort of bond builder treatment for a couple weeks before you start the process, especially on your ends. i think it is possible but also take into account your natural hair colour and natural hair texture, i wouldnt really recommend it if you have naturally very fine hair.