S Corp: Change in ownership and existing debt

My company is an S Corp incorporated in FL with equal equity split between my partner and I. My partner is going to resign, and a new partner will be taking his place.

What do we need to do to make these changes?

We have existing debt of $200k that is personally guaranteed by my existing partner and I. Will his resignation mean that the ownership of this debt will fall upon myself, or myself and my new partner?