I usually create custom curves myself, since they offer much more flexibility, but it’s also very easy to reset the default LFO shapes to any position you want. All you have to do is add the position you want to the reset command, for example: x600, x640, x680, x6C0, etc.
When using the default sine shape: x600 resets the phase to the center point and then continues sweeping upwards (to the right), x640 resets to the highest point and then continues sweeping downwards, x680 resets to the center point and then continues sweeping downwards, and finally, x6C0 resets to the lowest point and then continues sweeping upwards.
The other shapes respond slightly differently, but it only takes a few moments to experiment and see what’s happening.
Here’s a very handy animation by vV from a thread earlier this year:
Unfortunately it’s not yet possible with the Flanger, Chorus, Phaser, or Ringmod (and I’m probably forgetting a few other devices). I would definitely love to see an LFO Device style phase reset function on all devices though, just because I’m a total control freak.
In buzz there was some phase machine where there were slider to manually shift frequencies so that the effect was under total manual control. Boy did I love that effect. Unfortunately I haven’t seen one since. If someone has a hint gimme a link, pleeze.