There are a variety of methods for doing what you describe, but there is no built in function that will do it with a single keystroke or mouse click.
Interestingly all the methods take between 3 and 7 seconds depending on dexterity of operator and spec of computer
The simplest is just using the mouse. Click the fade icon, drag the target cue to the fade, click the master fader to turn it yellow on the levels tab, click the stop box (my time 5s)
The next would use keyboard shortcuts. cmd-6 for the fade/ T to put the cursor on the target/Type the cue number of the target/ enter/ grab the mouse/ click the master fader to turn it yellow on the levels tab, click the stop box (my time 6s)
You can cut and paste an existing fade and retarget it by dragging a new cue on top of it (my time 4 s)
If you have a paid for version then you can get into the wonderful world of applescripts
Basically you would create a script cue with a Hotkey say ctrl-F and paste something like this script from Rich Walsh into the script tab
set userDuration to 10
tell front workspace
set originalCue to last item of (selected as list)
set originalCueType to q type of originalCue
if originalCueType is in {"Group", "Audio", "Video"} then
make type "Fade"
set newCue to last item of (selected as list)
set cue target of newCue to originalCue
set duration of newCue to userDuration
newCue setLevel row 0 column 0 db -120
if originalCueType is not "Video" then
set stop target when done of newCue to true
end if
set q name of newCue to "Fade out: " & q name of originalCue
else if originalCueType is "Fade" then
set originalCueTarget to cue target of originalCue
make type "Fade"
set newCue to last item of (selected as list)
set cue target of newCue to originalCueTarget
set duration of newCue to userDuration
newCue setLevel row 0 column 0 db -120
if q type of originalCueTarget is not "Video" then
set stop target when done of newCue to true
end if
set q name of newCue to "Fade out: " & q name of originalCueTarget
end if
end tell
You might keep any such script in a separate cue list and eventually you will probably have a template workspace with a whole library of these scripts.
Now all you have to do is select the cue you want to fade with the mouse and press ctrl-F (or whatever hotkey you have set) My time 3s.
So in reality I think you can programme around 10 fades a minute and using one method over another might save you 5 or 10 minutes a day.
The fade script cue on a hotkey is a really useful tool and is my standard method.
Mic