If you have already written automation, you can modify automation data for track volume and send levels in real time by using Trim mode. When a track is trim-enabled, you are not recording absolute fader positions, but relative changes in the existing automation. See
Trim Mode for more information.
When a track’s Trim mode is enabled, its Volume and Send Level faders turn yellow, and its Automation Mode selector is outlined in yellow. This outline appears solid if the track is trim-enabled, and flashes whenever trimming is occurring on the track’s volume or send levels.