Entry prior to 1 year with Re-entry Permit

[jayesh1312000]

If I take a re-entry permit can I still re-enter prior to 1 year?
How about, return in less than 6 months? Do they actually take your G.C. when you apply for re-entry permit? Note, I do not have a GC but am planning to leave shortly after my I-485 gets approved.

Thanks.