There are detailed instructions within other threads....
Use the search function ("Reset Xforms") within the Omnibus to start.
In short form:
Depends on which software or plugin that you are using.
In max the function can be found in the utilities rollout (the hammer, upper right of main screen)
However it will require that the your hierarchy be disassembled and then after reset you will need to collapse the modifier stack on each part of your model and then re-assemble the desired hierarchy. Very labour intensive, but it should instead become necessarily part of your standard work flow procedure.
Alternately:
In MDA's NWmax plus (v5.06.01) plugin, it can be found under Mesh Tools. It has the advantage of working without having to disassemble your hierarchy. It automagically does the whole procedure, but you will want to be sure that Safe Pivots is selected. Btw, it won't cope with skinmesh, so you'll have to fix your hierarchy after resetting. (other elements of your fine wip may also require adjustment)
Carry on...
