Automatic generation of rules is the subject of the NCGB part of this document. Since running the NCGB code requires C++, you may not have it. Here NCSimplifyRationalX1[] does the trick.
Lying around in the directory NC/NCAlgebra/OldmmaGB/ is a primative NCSimplifyRationalX1[] which works entirely under Mma. We don't support it since our efforts go to Mma C++ hybrids. We do not even recall its name. Anyone who resurrects it must be an intrepid adventurer.