yes it is possible,
but the difficulty in doing so depends on
1) how far away your UAI was to the usual cut-offs for that course
2) how well u do in your 1st yr tertiary subjects
yes its possible. there are various factors which will determine the difficulty of your transfer. eg. popularity of course, number of available positions, your first year marks etc. you'll definately have to apply through UAC like you did before.