Service officers are reminded that an alien on whose behalf a change of nonimmigrant status has been filed and who travels outside the United States before the request is adjudicated is considered to have abandoned the request for a change of nonimmigrant status. This has been, and remains, the Service’s long-standing policy. The Office of Adjudications has described this particular policy in numerous letters and correspondence with the public and the legal community.
If at any time it comes to the attention of the Service that an alien on whose behalf a request for a change of nonimmigrant status has been filed has travel outside of the United States during the pendency of the request for a change of status, the application or petition should be denied pursuant to 8 CFR 248.3(g).
如果你申请了延期、并在尚未批准时离开美国，上述分析并不适用。司法部在该备忘录后面有注明：「Please note that the reference contained in the article to a October 20, 1999 letter written by Thomas Simmons is not germane to this issue because it relates to the filing of an extension of temporary stay, not a request for a change of nonimmigrant status. Current Service policy does not preclude an alien from traveling outside of the United States while a request for an extension of temporary stay is pending with the Service.」
假如你是 H-1B 、申请了 extension，在移民局批准之前出国了。若移民局在你走后批准了延期，你需要拿到 I-797 批准件、去领馆申请新的 H-1B 签证，才能在入境时激活新的 H-1B 身份。假如延期已经获批并生效，但你持尚未过期的旧 H-1B 签证入境，CBP 官员会按照旧签证的有效期给你 I-94，与此同时，你延期的身份将会失效 —— 这叫做「last action rule」，参见我们的文章解释：《移民局「最后生效」政策｜同时有多个申请或待审期间离境的后果》 。
上述案例中，只要你旧的 H-1B 签证尚未过期，你可以使用它合法入境，但是 CBP 官员给你的停留期限可能会远远短于你延期之后的新身份；你可能在入境之后不得不重新申请延期。