PS- Network Teco - Undo ?

Dear PS gurus,

Request pl help in how to do undo if the Network is technically completed (TECO) applied in Network & saved.

In Project WBS & Definition, we have provision of UNDO or cancel the TECO & Close, but in network, we don't find the undo/cancel in Status, why?

Pl help, thanx in advance

Regards

Srihari