It depends on the performance in P1. If it's good, I'll let my kid transfer in P2 rather than apply P1 again.
My friend's daughter (borned in Nov) was on the waiting list of Co-ed last year and the staff told them just let her studying in an aided school and apply again next year. My friend & her husband were planning to do it this way but when they saw their daughter's very happy with her school and asked not to transfer, they changed their mind.