I am currently on a Green Card job. I was looking for a new job since some months and finally have got the offer.
I have some doubts about switching the job on Green Card work permit. I will be thankful to you all for sharing
your own experiences.

1) First of all is there any legal obligation after signing the contract with new company that I must join? or I can refuse
joining after signing the contract?

2) After informing my current employer about my intentions to leave, should I inform arbeitsamt as well?

3) When should be the new residence permit and work permit be issued? after joining the new company or just few weeks before joining?

4) I have unlimited contract (means only the starting date mentioned and no end date). My employer has informed me that the
authorities only issue a residence permit till the validity of passport (which is seven more months in my case). Is this
the normal way? So it means when I get the new passport I will get the residence permit only for few months?

Looking forward for your suggestinos !

Nanda