Yes, you can technically change jobs while your I-140 petition is pending, but doing so can significantly impact your green card process. If your I-140 is employer-sponsored and you leave that employer before the petition is approved, USCIS may deny the petition because it is tied to a specific job offer. In most cases, it's advisable to wait until the I-140 is approved before changing employers to preserve your priority date and eligibility for adjustment of status.