Using Polygon to get historical data for changed tickers

What’s the trick to this? I’m not sure the technical term, but for example, trying to get minute bars for “RTX” before April 3 2020 returns zero results I’m guessing due to the Raytheon/United merger. Polygon claims to be free from survivorship bias so I’m assuming there’s a way, but I haven’t found it.

My bad here - was under the impression that the RTX symbol was held over from United, which was traded as UTX - so I can get UTX and RTN from before the merger date just fine.