You're welcome. Some posters sometimes have overly long posts and it makes sense that the unwanted stuff get deleted.
<blushes> Of course you cannot have any specific TERBore in mind </blushes>
I have two brief points to offer: If the post you're replying to is just before yours (and especially, if it is also a lengthy one, as
Darts mentions) it isn't helpful or necessary to quote it at all, just a reference to its position above and/or the Poster's handle or the point that inspired you to respond will make all the connection needed to the original. Quote only if a quote is needed
But secondly if you are also moved to edit someone else's post, and only use part of it in your Reply, honesty, simple courtesy and the long-established practices say you owe it to everyone to mark where you edited. Traditionally that's with the three dots called ellipsis … ([Option key] along with the [;] on Macs. Windows seems to use the numberpad , if there is one) which can be done with three periods ... . Of course if you change anything within the quote, honesty again requires you note that in [square brackets]. No invisible, unlabelled edits.
If all you want to do is highlight some relevant bit you are responding to specifically, Bolding and Italic don't work inside a quote, so you'll have to use the Arial Black font, underlining, or change text colour.
OK, so it was three points, but still short. Sorta