How to get "opposite of delay" effect?

In search for the perfect groove I might want to experiment, what if I either delay my vocal tracks a bit (no problem with ReaDelay) or what if I move them earlier in time, perhaps just some milliseconds. I can of course move them earlier in time by moving the actual takes, but this gets troublesome if I have constructed the vocal track from multiple takes on multiple tracks. So instead of adjusting the positions of each take and experimenting I would just like to have a similar effect in use like I have for the delay (I actually tried if ReaDelay accepts negative values as amount of delay - unfortunately it does not). Thus currently I do this kind of experimentation so that I delay everything else except the vocals in order to see the effect of having the vocals a bit ahead in time. Is there an easier way to do this?

hi - try the 'JS time adjustment' plug. does what it says! :)

I think there's something wrong with the "dry" slider, because it adjusts the wet signal