Sot of. The EU won't negotiate new terms for us staying, and shouldn't have to, but what they can do is negotiate new trading terms for when we leave.
Given this new information, then a second referendum could be held on whether to stay, on existing terms, or leave, and accept the new ones.
In theory, if you invoke the article 50 you are out. You have two years to find an agreement with the EU and after that they can refuse to discuss with you.