So I see talk of round trips with regard to the PDT limit........
IF, and it's a big IF, you're an option trader, and you take a trade in a long call position ("I just bought $SNDL $.50 calls for Feb19, woohoo!") and then you want to take profit WITHOUT being hit with a round trip, you can then SELL a different strike up to get money out of the trade and leave yourself with something to work with (" My calls are up $.30!!! I guess I'll sell the $1 calls for the same date at $.40 to take the risk off). You now have .50/1 calls spreads and since you dealt with two different products (.5 calls, 1 calls) this is NOT a round trip and you were able to mitigate risk.
The next day you can decide what to do with your spreads, HODL, sell, etc.
***If this post is on Business and Investing, take it with a grain of salt. I am wrong way more than I am right (but I am less wrong than I used to be) and if you follow me you will be too.***
B&I Key:
ETH - Extended Trading Hours --- RTH - Regular Trading Hours
ORH - Opening Range (1st 30min) High --- ORL - Opening Range Low
R1, R2, R3 - Resistance 1, 2, or 3 --- S1, S2, S3 - Support 1, 2 or 3