Sorry about that bro - Leupold apparently has a pretty good webmaster.
Here is the information, copied directly from Leupold:
How do I Zero the Windage and Elevation Dials After Sighting Zeroing the Windage and Elevation Dials After Sighting In All Leupold scopes feature adjustment dials, either numbered or with an indicator, that can be repositioned to align the marked zero of the dial with the position indicator without changing the adjustment setting of the scope that was achieved when sighting in. This allows the shooter to know the original zero of the rifle in the event further adjustments are made in the field. To reposition the dials on Vari-X II and Fixed Power models, move the outermost dial so that the zero aligns with the stamped line indicator mark on the top of the adjustment screw that is perpendicular to the coin slot. Vari-X III models have a pointer dial that moves with the adjustment slot. This dial also can be moved independently to align with the zero on the outermost dial. To reposition this dial simply rotate it until the pointer is aligned with the zero. To reposition the dials on Target and Tactical models: 1. Loosen the set screws that surround the top of the knob until the cylinder turns freely. 2. Move the cylinder dial by hand to align the zero with the white perpendicular mark at the base of the cylinder. 3. Tighten the set screws until the cylinder is secure.
I think you have figured it out by this time! But to make it simple the markings on the turrets of your scope are marked for the direction "you want your point of impact to move" to get the rifle zeroed. The reticules will move in the opposite direction from how the turrets say. Because you are actually moving the reticle from where you were aiming to the previous point of impact that is why they are doing the opposite as marked.
It makes it much simpler if you just look at the turrets and think I am moving the turrets in the direction I want the point of impact to go. Example if I am hitting 4 inches left of the bulls-eye I want to move the turret Right as marked! When in reality the cross hairs are acutually moving left if I was looking through the scope while I made my right turret adjustments. Hope this also helps in addition to what the others have advised. The 4 inches mentioned at 100 yards on a 1/4 inch (1/4 Min.) adjustment Scope would be 16 clicks to the Right for example to get zero. Or 4 MOA.
I don't know what kind of rifle you have this mounted on, but you might try a boresite laser. I use mine at night on my neighbors garage door. I set it in a bench vise in my shop, and shoot the laser on his door and adjust the scope from there. We have measured the distance at 50 yards and then I go to the range and I know I'm zeroed at 50 yards. Do the math from there.
Some cheap scopes are not set to zero out of the box. I have an NcSTAR scope on my 10/22. The knobs were several turns from zero. A friend has a decent bore sight that I used to get the scope hitting on paper. Once I got the scope zeroed in I used a white out pen to make a small mark. There is no way to move the adjustment ring to a new zero. The scope has survived this summer very well. The only time I had to reset the scope was my own fault. I didn't tighten the mounting screws properly.
I haven't used Tasco's in years, and I seriously doubt that it has the ability to reset. Anyway, It may as simple as pulling upward on the dial itself until you feel a release, then reset. If it doesn't move then I'd say it doesn't have a reset. Sorry I was no better help than that.