Tax-wise technically speaking, this is not a sale. It's simply a transfer of all assets from one partnership to another partnership.I am assuming the old partnership is disolved no longer exists. This means that the EIN for the old partnership is also retired permanently and forever. (it "matters" if my assumption is not correct here.)
As far as taxes are concerned, this is not a sale because the members of the old and new partnerships are the same.
Basically, the owners of the old partnership will distribute all cash and other assets of that partnership, to themselves. This is done by indicating each partner taking back a return of all capital contributions they each made to that partnership, along with the distribution of any cash to each partner. This means the 1065 for that partnership will be marked as "final" and the 1065 itself will also be a "final" 1065 return. This distribution and return of capital investment to each partner occurs on the date as recorded at the courthouse.
The new partnership (or partnerships if there are two, with one for the single family and another for the multi-family units) will record each member making a capital contribution to the new partnership, of the assets that were removed from the old partnership. The date of the contribution "must" be at least one day "after" the old partnership disposed of the cash/assets to the members. This is because you can't have two entities, each having 100% ownership of the property on the same day.
This means that the change in cost basis will not change "INITIALLY". But it will change for the new partnership. First, let me explain this, because it matters when it comes to real estate property; especially rental rental estate.
Your cost basis allocated to the land *WILL* *NOT* change for any reason, under any circumstances, since land is not depreciated. Your cost basis of the structure and any/all other depreciable assets must be reduced by the amount of depreciation already taken on that structure/asset by the old LLC. Then depreciation starts over from year one, using the new, lower cost basis.
The $500 spent to record this change at the county level is "NOT" reported as a purchase/acquisition cost. That's because you can't sell something to yourself. Since the membership of both the old and new LLCs are the same, you can't be both seller and buyer of the things that were "sold". It should be reported/claimed as a miscellaneous expense that I would just label a "title change fee" or more accurately, a "title correction fee" if that's all that was really changed at the courthouse.
To report it on the taxes as a sale, means that you're taking money out of your left pocket that you've already paid taxes on, and put it in your right pocket only to pay taxes on the same money "again". That's just wrong, any way you look at it.
