Seven letter words change one or two letter to make a new word

automat

AutoCAD

caution

faction

noticed

diction

fiction

unction

auction

actions

factors

factory

faction

factoid

astroid

I believe asteroid has an e, unless you’re talking about a particular mathematical curve: a hypocycloid with four cusps. Specifically, it is the locus of a point on a circle as it rolls inside a fixed circle with four times the radius. :wink:

destroy

astride

strange

Yes, the mathematical curve.

derange