Exchange Apartment

I would like to exchange my nice apartment with another apartment or with a 2 persons shared flat, in Heidelberg or Mannheim.
My little apartment is located in Rohrbacher street near to Bismark platz; It is very nice and stylish and in a new building and completely in a quiet place; but because i have sometimes guests, so it's too little for me.
This is fully furnished and everything is included in the rental price (also Internet and Electricity). There is no deposit for this apartment.
please remember the determinant decision is taken by the owner, but if everything goes well i try to persuade the him.
Long or short term contract both are possible but not endless.
Please consider, only if you want to exchange contact me, then each contact would be welcome :)
If your case is more expensive or cheaper, it doesn't matter just inform me about it please.