There's two parts to this answer.
In regards to "abandonment of status", the law states that the Adjustment of Status application (AOS/I-485) is automatically considered abandoned if you depart the US and don't have a valid work visa (L-1, H-1 or H-4, L-2 for their spouses), a valid spouse visa (K-3, K-4), has a "V nonimmigrant visa, or an Advanced Parole document (I-131).
Then, there's the concept of "dual intent":
A common requirement for nonimmigrant eligibility is that an alien
seeking such classification have nonimmigrant intent rather than
immigrant intent. In other words, an alien may not intend to remain
permanently in the United States (i.e. immigrant intent) without
jeopardizing his or her nonimmigrant status. This requirement usually
manifests itself as:
- a need to maintain an unabandoned foreign residence abroad; and
- a presumption that the alien is an immigrant until the contrary is established.
However, not all nonimmigrant categories are subject to these
requirements. Where they do not apply, it is often possible to apply
the doctrine of "dual intent". Dual intent means an intention to
immigrate at some time in the future while properly maintaining a
nonimmigrant status in the present.
The full list of "dual intent" visa categories is:
H-1B temporary workers in a specialty occupation
H-4 dependents (spouses and unmarried children under 21 years old) of H-1B workers
L-1A itntracompany transferees executive or manager
L-1B intracompany transferees specialized knowledge
L-2 dependents (spouses and unmarried children under 21 years old) of L-1A or L-1B workers
O-1 aliens with extraordinary ability in sciences, arts, education, business or athletics
O-3 dependents (spouse or unmarried children under 21 years old) of O-1 visa holders
K-1 fiancé(e)s of U.S. citizens
K-2 dependents (unmarried children under 21 years old) of K-1 visa holders
K-3 foreign spouses of U.S. Citizen
K-4 dependents (unmarried children under 21 years old) of K-3 visa holders
V dependents (spouses and unmarried children under 21 years old) of U.S. lawful permanent residents.
As we can see, there's a big overlap between "dual intent" visas and visas where one can leave without automatically abandoning one's I-485: the four visa types not included are O-1, O-3, K-1 and K-2. From this we can infer some logic in the law:
- If you're on a "dual intent" visa, you're allowed to file for a Green Card within the country without breaking your presumed "nonimmigrant" status. Hence if you come back from abroad after filing an I-485, you'll still be allowed to enter.
- If you're not on a "dual intent" visa, leaving the US and coming after filing for a Green Card will result in trouble, as you've now indicated that you're no longer a "nonimmigrant" by filing for a change of status.
- Hence as as far as the US government is concerned, leaving the country without an Advanced Parole document means you won't be able to come back legally within the same status. And if you can't come back, the application to "change status" becomes moot.
- O-1, O-3, K-1 and K-2 are all supposed to be "dual intent" too, but presumably they were just forgotten about while drafting the law.
The logic is somewhat convoluted due to the whole charade of "dual intent" but that's just US immigration law for you.
