I try to HermiteDecomposition a symbolic matrix as follows but failed:

In[27]:= Array[x,{2,2}]
Assuming[Flatten[%] \[Element] Rationals , %//HermiteDecomposition]

Out[27]= {{x[1, 1], x[1, 2]}, {x[2, 1], x[2, 2]}}

During evaluation of In[27]:= HermiteDecomposition::latm: Matrix contains an entry that is not rational.

Out[28]= HermiteDecomposition[{{x[1, 1], x[1, 2]}, {x[2, 1], 
x[2, 2]}}]

I would like to know if there is a way to do this sort of thing. My goal is to feed the resulting Hermite Norm form to Solve to construct a system of equations.

Regards,
Zhao