shankar88 said:
is it possible to change the course from pg diploma to mba after going to canada?
Yes. But you will have to inform the CHC in that case as you are moving from a lower level course to a masters course.
Also you must know that MBA = University and admissions deadlines for universities for Jan intake are long gone and of Sept '12 intake would be around Jan mid-end. And admissions to reputed Universities is definitely not a cake walk.
Also not to forget that to get admission in a reputed university for MBA you need a good GMAT and IELTS score.