ΔE 18.8, loose: different enough that you should pick on purpose. Pallid Wych Flesh is a little darker, much more muted, warmer than Pastel Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Pallid Wych Flesh is a little darker, much more muted, warmer than Pastel Blue.
The same difference applies the other way round: Pastel Blue is a little lighter, much more saturated, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Pastel Blue on the colour wheel See Pallid Wych Flesh on the colour wheel
All matches: Pastel Blue equivalents · Pallid Wych Flesh equivalents