Is possible to symetrize a mesh usint the same vertices on the model ?

Explaining what I want to do is lik ethat ... I have messed the vertices of my model and is no more symetrical , the vertices for both sides of the x y z axes are the same but are moved , repositioned rotated etc .. is it possible to choose one good side and mirror it's arrangement on the other side ? may be just on portion of vertices?

3dsmax btw ...

Symmetry modifier? hmmm... in case you are refering to something else... dunno

select the faces of the bad side, delete, mirror the good side, attach the two meshes and weld the centre verts....is it that simple or am I missing something from the question?

seth - you're missing the aforementioned symmetry modifier, which does the same thing but faster and easier

ahhh, still learning the ropes with 3ds....I will have a play with that then thanks poopipe

For max. http://www.rpmanager.com/plugins/Transmographier.htm
What you meen is called TOPOLOGICAL symmetry - I.e. the topology on both sides of the mesh is identical, but not the actual positions of the vertices. Symmetry modifier sucks if you need to symmetrize an already unwrapped or even skinned mesh. Without it you often can't apply symmetrical features of further procedures (like skinning).
But if you simply wanna mirror your WIP geometry - don't make a fuss - use Symmetry modifier. That's all you need in this case.