ΔE 11.8, fair: the same colour family, but not a straight swap. Glacier Blue is a little darker, more saturated than Morrow White.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Glacier Blue is a little darker, more saturated than Morrow White.
The same difference applies the other way round: Morrow White is a little lighter, more muted.
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 Morrow White on the colour wheel See Glacier Blue on the colour wheel
All matches: Morrow White equivalents · Glacier Blue equivalents