The main "gene" controlling eye colour (which we'll separate into "brown" and "blue", for ease), is actually two genes, albeit very close together.
The first gene is called Make Brown.
The second gene is called Turn The "Make Brown" Gene On.
(Note: these are not the actual gene names
)
You can have DNA changes in Make Brown, such that it doesn't actually make brown pigment, hence blue eyes.
You can have DNA changes in Turn The "Make Brown" Gene On, such that Make Brown is never activated to make brown pigment, hence blue eyes.
If...
Parent Blue Eye 1 has a DNA change in Make Brown but a working copy of Turn The "Make Brown" Gene On
and...
Parent Blue Eye 2 has a working copy of Make Brown but a DNA change in Turn The "Make Brown" Gene On
...it is perfectly possible for them to have a child with working copies of both Make Brown and Turn The "Make Brown" Gene On
But as others have said, it more complicated than that.