If an individual filing a green card under employment-based category has
changed job and now planning to port priority date from previous filed Labor
certification, he will at least need an approved I-140 from previous
employer to recapture priority dates.
As per Yates Memo, in the context of employment-based immigration, visa
petitions filed under the EB-1, EB-2, or EB-3 categories are entitled to the
earliest priority date where a subsequent I-140 immigrant visa petition in
any of these categories is submitted and approved, unless the prior petition
was revoked due to fraud. So, unless case is revoked due to fraud, you
should be able to recapture old priority date.
But there are many cases with USCIS, where old priority date is not
recaptured on new filings even if previous employer revokes old approved I-
140 due to retaliation or due to company's policy to annually revoke cases
for former employees. In these circumstances, employee or new employer
should call National Service Center and talk to representative and remind
them about Yates Memo, which clearly says earliest priority date should be
recaptured unless petition was revoked due to fraud or misrepresentation. If
you will talk to them nicely and puftorth your case by referencing Yates
Memo, you might be able to convince them to recapture old PD. See excerpt
from Yates Memo below.