Delayed Exchanges and Timing Rules

Classically, an exchange involves a simple swap of one property for another between two people. But the odds of finding someone with the exact property you want who wants the exact property you have is slim. For that reason, the majority of exchanges are delayed, three-party, or Starker exchanges (named for the first tax case that allowed them).

In a delayed exchange, you need a qualified intermediary (middleman) who holds the cash after you "sell" your property and uses it to "buy" the replacement property for you. This three-party exchange is treated as a swap.

There are two key timing rules you must observe in a delayed exchange:

45-Day Rule

The first relates to the designation of a replacement property. Once the sale of your property occurs, the intermediary will receive the cash. You can't receive the cash, or it will spoil the 1031 treatment. Also, within 45 days of the sale of your property, you must designate the replacement property in writing to the intermediary, specifying the property you want to acquire.5 The IRS says you can designate three properties so long as you eventually close on one of them. You can even designate more than three if they fall within certain valuation tests.6


https://www.investopedia.com/financial-edge/0110/10-things-to-know-about-1031-exchanges.aspx



The reason it matters is that the tax treatment is for asset swaps, not reinvestments. The intermediary is necessary to rig the transaction to look like a swap. You are then swapping with the intermediary not the seller. Done it several  times for my rich bosses and always used an attorney. Generally a flat fee of $800-1000

You should always bounce the big transactions off your tax advisor first