How should my partner and I set up this partnership?

[Ryan Alexander]

Hey everyone, have a question on partnerships. I'm a realtor in Pittsburgh representing an out-of-state investor on a triplex. We're under contract in the name of his LLC and closing soon. We've now decided to partner up on the deal 50/50. This will likely be a one off for both of us. What's the best way to set the partnership up since we're closing soon? Should we add my LLC to the sales agreement, which may be an issue for his lender and back the closing up OR do we continue with it closing in his LLC name and wait until after closing to draw up an agreement with an attorney between the two LLCs? What havs you all done in a similar situation when setting up your partnerships? Any help/advice is appreciated!