If I understand correctly what you're asking, you'd just put it on an aux channel and then send signal to it from your desired channels. You'd want to make sure that Chorus/Chorale Mix is set to 100% or, if you're only using Detune, that Detune Mix is set to 100%. When you set Chorus/Chorale Mix to 100% it will say "Vibrato" because Vibrato is just the wet portion.
The sound of chorusing comes from the combination of the wet and dry signals (traditionally with a 50/50 blend), so if you were to listen to the send on its own, you wouldn't necessarily hear chorusing, but you will once the output of the aux bus is mixed with the signal from the channel.
You might also probably need to adjust the output level of your source channel to account for the increased volume created by the send. One trick that you might try is throwing a compressor before or after the chorus on the send bus–pre would affect the way the ENV->MIX and ENV->RATE controls affect the sound, whereas post would not–and adjusting the threshold and ratio so you can have chorusing that only appears as the sound decays. (You can achieve a similar effect with ENV->MIX, but it also changes the amount of the dry signal in the mix)