My question is if your GC is employment-based, can you change your current job category? or can you take multiple jobs in different areas at the same time? Does it affect your USC later? Thanks. AC21 is not applying here, but listed for your reference. Thanks.
Cited from http://immigrationroad.com/green-card/ac21-port...
AC21 Portability is for Change of jobs before I-485 (Green Card) is approved. To be eligible for AC21, your new employment must be the "same or similar" occupational classification to the one described in initial Form I-140. There is no clear definition of what constitute "same or similar," but a USCIS adjudicator will consider the following factors:
Job Description: your job duties of the new employment will be compared with the job descriptions contained in your I-140 or labor certification (ETA 750A or new PERM).
DOT code and/or SOC code: Your DOT code or SOC code assigned to the I-140 based on your labor certification, or an appropriate code determined by the adjudicator if LC was not required, will be used to judge whether the new employment is the same or similar occupational classification.
Wage information: your new salary should not be significantly different from the previous one. However, it doesn't have to be exactly the same or necessarily higher.
Note that AC21 does NOT specify:
The new job must be in the same geographic location; or
The new job must pay the same or a higher salary; or
A new labor certification must be filed.