Sorry to add a question to your question.... but I was also wondering about the whole shift change and/or transfer thing. I have read that at a regular sort HUB that there is a sign up sheet and after 6 month (article 22 section 4) you can put your name on it to move to a different job or shift with in the HUB.
AIR OPERATION are run under Article 40.
Article: 40, section 3 (friend) (2) states it takes one year before you can move to a different shift and/or job.
I work at a small (12-14 people) UPS airport sort facility. All or the rampers are contract workers (lower pay, no benifts) from the FBO across the airport, so I real don't have the answers for your question. Everyone here is on a 3 hour shifts.