It depends what kind of diploma you're doing.
So for example in my case, I will be studying in Ontario and I got admission in a Advanced Diploma (which is 3 years long) and as per the program, if I maintain a certain GPA, I can put in another 12 months and get a bachelors awarded from their partnering university....
So for 2 year diploma, you would need to apply in a university and then get your credits transferred.