That's sort of a murky description.

You can change bases on the same airplane as soon as there's a bid open after you start indoc, even if it's the first day.

If you want to just switch to a different plane in your current base, or switch to a base that also has your current plane, then it's 24 months.

If you want to switch to a base that does not have your plane, or if the other base has your current plane but you do not have the seniority to hold your current plane in that base, you can switch to a different plane after 12 months, but you add the remaining 12 months to your new 24 month seat lock, meaning you will be locked for 36 months.

Also, when we say "switch bases", what we really mean is you can bid on the first bid where the first conversions start after your seat lock deadline (12 or 24 months). You could still wait another 9-12 months to actually train/transfer, so you could be stuck in your new hire spot for a while depending on the timing of things.

In practical terms, if you get the 320 or 737 right off the bat, you will have no issues since every base now has those fleets so you'd just need a transfer on the first bid that happens after you get hired. Other fleets will be more restrictive, so depending on which domicile you want to end up in you'll want to structure your initial bid accordingly. If you want LAX, don't bid the 717 or 220, for example, since neither plane is there. Basically figure out which planes are in your desired domicile and prioritize those first.