Can Wife use Husband’s Priority Date or vice-versa to Interfile I-485?

While talking to my friends this has been a very common question, if a derivative (dependent) beneficiary can use primary beneficiary’s priority date to file I-485 under employment category.

What is Interfiling?
Interfiling is a procedure that allows an applicant to change the I-140 petition upon which the I-485 is based. Essentially, the I-485 is filed based on an I-140 petition, but the applicant wants to proceed through a new or different I-140 petition. Interfiling permits the individual to "switch" the I-140 upon which the I-485 is based. This is true for the cases where an individual has just ported their case from one preference category to other (e.g. EB3-EB2) and already has I-485 pending with USCIS based on earlier priority.

Can Wife use Husband’s Priority Date or vice-versa to Interfile I-485?
In a scenario where both husband and wife have independent I-140 petitions filed by their respective employers, and where there is a set of I-485s (one for the primary spouse and one for the derivative spouse) filed with regard to one of the I-140s, there is no option of interfiling based upon an I-140 approval for the derivative spouse, even if his/her preference category is better and make them eligible to file I-485 based on primary’s priority date. This is because the roles of derivative spouse and primary applicant would have to be reversed in this situation. There is no mechanism when interfiling to shift applications from derivative to primary and from primary to derivative, therefore making them improperly filed with the other I-140 petition. You cannot mix and match your priority date to take advantage of both worlds.

Of course, if the same person has an EB3 and now an EB2 I-140 petition, the USCIS will allow the EB2 I-140 approval to replace the previously-filed EB3 I-140 petition approval.