"CONVERSION" TO PERMANENT RESIDENCE
Once the L-1 Visa beneficiary has performed the executive or managerial task within the United States, he or she must leave the United States. 

However, if the United States-based corporation proves to be viable after being in existence for more than one year, the foreign-based corporation may deem it necessary to retain the L-1 transferee in the United States permanently.  In this case, it is possible to apply for permanent residence for the manager or executive as a priority worker.

It is not necessary to first transfer a manager or executive to the U.S.A. before applying for permanent residence.  If both corporations have been in operation for more than one year and the manager or executive qualifies, it is possible to apply for permanent residence as a priority worker without first applying for the L-1 visa.