Assignment vs referral

What is the difference between assignment vs referral? If I had to guess assigning a park at closing would involve tying up the property, performing due diligence, trying to sell the property to a 2nd buyer and making as much as possible on the difference. And a referral, would simply mean typing up the property, having somebody else do the due diligence and taking the 5% off the sale price.

I’d say referral is more like, “Hey, I know a park for sale. Do you want me to introduce you to the seller?”

Wheres the assignment is you tying the park up with an agreement and selling the park to another investor for a greater amount that you were going to pay for it.