How can I file a status change for EB-5 while on a B-1 visa?

If you are physically present in the United States in valid non-immigrant status and there is an immigrant visa number available, i.e., your priority date is current, you can file for your adjustment of status after 90 days. Your qualifying dependents (spouse and unmarried children under 21) can follow to join you later through immigrant visa processing at the U.S. embassy or consulate in your home country.

You can just file an I-485 as you are currently in B-1 with time left on your I-94. Your dependents, however, cannot start the process if they are overseas until you become an LPR and then you need to file the I-824 to split the process. Best to all consular process or all adjust.

If you are in valid status, and you had entered lawfully, and the underlying petition is approved, you can generally file for an adjustment of status for permanent residency. Dependents can "follow to join" after the primary adjusts.

If your priority date is current, you can file to adjust your status in the United States. Yes, the PA can do so in advance of the dependents.

While it is theoretically possible to adjust status as long as you have lawful status in the U.S. at the time of filing, be careful with your timing and explanation because you do not want to accidentally trigger immigration violations. For B-1/B-2, the most common one reason why a case may be denied is filing for adjustment within 90 days of entering and triggering immigration intent. Check with your immigration attorney first before making any decisions to make sure you are in the clear.

There are many challenging issues, but if you can show that you had no intention of filing for adjustment when you entered, this may be viable. If they determine you entered as a tourist with a plan to stay then you may be barred forever.

You change status by filing an I-485 if the visa is currently available. Yes, the principal can adjust without the dependents.