Returning to the previous employer, should green card process start all over or not??

[Immigration1987]

My I-140 is approved from company A in year 2013. Switched to company B in 2015. Company B also filed green card.Now, I am planning to go back to company A after working for couple of years in Company B. Does Company A has to start Green card process all over again or since I already have an approved I-140 with Company A, I can use the same one?  

[Indian_TX]

You can use the same 140 from A if they haven't withdrew it.

[Immigration1987]

Thanks. Does the Title of my position should remain same while returning or It can be different and I can still use that same I-140?