Have been in the East Coast building for 1 1/2 years.  Love the apartment but hate the job so may need to relocate out of the city in the next few months before the end of my current lease.  I'm unfamiliar with subletting or assigning a lease ... what exactly is the difference?  Is it relatively easy to do?  Other alternatives ... is there a way a lease can be broken by paying a penalty?  Any advice or experiences from others who've done this would be most appreciated.

Check your lease; I doubt you are allowed to sublet or to assign without Rockrose's consent.  In that case, it's mostly in Rockrose's discretion to let you off the hook.  This here may help you a bit:  http://www.oag.state.ny.us/realestate/tenants_rights_guide.html

Subletting - Rockrose can come after you if anything goes wrong.

Assigning - Rockrose must first go after the new tenant and you are secondarily liable.  Always assign if possible.

Rockrose can't prevent you from subletting your apartment.  If they refuse to give consent you can override it, regardless of what they say. 

Previously shocka wrote:

Go speak with the folks in the leasing office. They will help you out.