Hello,

I am based at Bangalroe currently. I got a job offer from company A and then I applied for national visa. Based upon this company A I was issued a National visa with D category and I can see company A's name is written on my issued visa.

Now I got another job offer from company B and I am interested to join company B instead of company A. What should I do in this case?
1. Can I apply for another National Visa while 1st one is still valid
2. Should I wait for 1st one to get expired then apply for national visa again for company B
3. Should I just travel with 1st visa and once I reach Berlin then apply for Blue card on company B instead of company A?

Appreciate any clarification here. Thanks!

You should do 3rd one. Many of my colleagues have done this. Good luck.
 

As per my offer letter my joining date is on 1st October, 2016 and my Visa is valid for 90 days from 1st October, 2016.

Can I travel on 1st November, 2016? During the immigration check would there be a problem if my offer letter says joining date is on 1st October, 2016 but I am reaching Berlin on 1st November, 2016 ?

Now you started playing game. You should have asked this well before. Anyway, if your offer letter says 01.10 you should have reached here on or before that. If you are coming on 01.11, you need to provide additional confirmation from employer so that border police let you in. Having said all these, you will be able to work only when your visa is updated with right employer.

I am very much interested in joining the Company B. Can I take a route of appying another national visa  for company B while National visa of Company A is still valid

Should I approch consulate office to cancel my visa for Company A first then apply National Visa for Company B?