As I see it, the difference between a submissive and a slave can be boiled down into one word: Negotiation.

As I see it and as it has always been defined to me, a slave does not have the right to negotiate. Her privileges are decided by her master and may be revoked or suspended at any time, based upon her attitude and competency.

A submissive has the right to negotiate her rules and privileges and then not have them removed, unless under previously negotiated circumstances.

If a submissive doesn't like something about her relationship, she can change it. A slave, once she signs the contract of ownership or agrees to her masters collar, may not.