Hello Mark! This is called a 3-way installation and Eve light Switch (US, 3rd generation) supports it. Please make sure to have a neutral wire at home, mandatory for Eve Light Switch.
On a 3-way installation two light switches control one light. Only one is replaced by Eve Light Switch, the other 'dumb' switch remains in place but needs to be wired correct as well.

Please check the wiring:
quick start guide
**3-way starting page 8**

Best regards, Volker
Feb 17, 2023