  We performed $^{185/187}$Re nuclear quadrupole resonance (NQR) measurements
under pressure to investigate the superconducting properties of
noncentrosymmetric superconductor Cd$_{2}$Re$_{2}$O$_{7}$ under various crystal
structures. The pressure dependence of superconducting transition temperature
$T_{\rm c}$ determined through ac susceptibility measurements is consistent
with the results of previous resistivity measurements [T. C. Kobayashi $et
al$., J. Phys. Soc. Jpn. 80, 023715 (2011).]. Below 2.2 GPa, in the nuclear
spin-lattice relaxation rate $1/T_{1}$, a clear coherence peak was observed
just below $T_{\rm c}$, indicating conventional $s$-wave superconductivity. In
contrast, the coherence peak disappears at 3.1 GPa, suggesting a change in
superconducting symmetry to the $p$-wave dominant state against pressure.
