Please help - 485 question after 140 approved

My previous company filed 140 and 485 for me. But I have not started working for this company (due to many reasons). My 140 was approved last year but 485 is still pending (for 8 months already).Now I work for another company using EAD. My question is:can first company withdraw my green card application? If Yes, do I have to re-apply and go through the whole process again? Thank you for your help. _:)