2 Quick questions

[Tee76]

I moved to Canada in 1981 from Michigan when i was 5 years old.I lived there up until 2005( moved back to Michigan), so 24 years.My questions are:

If i reapply for PR status again (thinking of moving back to Ontario) will i still have or get to keep my same old SIN # (still got the card in my wallet) or will i be given a new one/number?

Secondly, is it possible to apply for dual citizenship while living in Michigan right now?

[Leon]

You can not apply for dual citizenship because you need to have been in Canada for 3 out of the last 4 years to apply.  Since you have been gone 4 years, you have officially lost your PR status for being gone too long.  You could try sneaking in and seeing if you can get away with it.  If you do, then don't try to renew your PR card for 2 years because then you will meet the residency requirements again.  If you would rather apply for PR again, you will have to relinquish your old PR first.