  We study quasi-elastic rescattering effects in B_{u,d,s}(bar) to DP, D(bar)P
decays, where P is a light pseudoscalar. The updated measurements of
B_{u,d}(bar) to DP decays are used to extract the effective Wilson coefficients
a^{eff}_1 ~ 0.90, a^{eff}_2 ~ 0.23, three strong phases delta ~ 53 degree,
theta ~ 18 degree, sigma ~ -88 degree, and the mixing angle tau ~ 9 degree.
This information is used to predict rates of nineteen B_{s}(bar) to DP and
B_{u,d,s}(bar) to D(bar)P decay modes, including modes of interests in the
gamma/phi_3 program. Many decay rates are found to be enhanced. In particular,
the B_s(bar) to D0 K0 rate is predicted to be 8\times 10^{-4}, which could be
measured soon. The rescattering effects on the corresponding B_{u,d,s}(bar) to
D(bar)P, DP amplitude ratios r_B, r_{B_s}, and the relative strong phases
delta_B, delta_{B_s} are studied. Although the decay rates are enhanced in most
cases, r_{B,B_s} values are similar to factorization expectation.
