Drag a connection's end to reconnect it, or drop it to remove it
Click a BaseHalf connection to select it, or drag a box that touches no card to select the lines it crosses. Drag an end onto another card to reconnect it, or onto empty canvas to remove it.
A line on a BaseHalf canvas is a connection you can change in place. You do not have to delete it and draw it again to point it at a different card.
Select a line
Click a line to select it, then press Delete to remove that connection. The files stay; only the connection is gone.
You can also drag a box that touches no card. Every line the box crosses is selected. Delete then removes them all as one step of undo.
Drag an end
Drag an end of a line and let go on another card to reconnect it there. Let go on an empty part of the canvas to remove the connection. Let go anywhere else, and the line goes back as it was.
An item cannot be its own upstream, so dropping an end onto the card at the other end of the same line does not make a loop. The line stays as it was.
Every one of these can be undone.
What this does not change
Lines are drawn only between cards in the same folder. A connection to an item in another folder has no line. To change one of those, open the card's badge.
A generated file keeps the inputs that made it, and a draft keeps its inputs while it generates. Changing them is refused, with the reason.
To draw a new connection, drag from a handle onto another card, or drop a handle onto empty canvas to create something that already lists the source as its upstream. The connections docs describe selecting a line, dragging an end, and what is saved.