Hi there! Cat here from the Front support team 🌻
If a teammate needs access to separate Front instances, the teammate will need to have an account in each instance that is linked to a unique email address. The unique address could be an alias or an adapted email (e.g. cat@company.com and cat+secondary@company.com).
The teammate will not be able to access both instances in the same app session (i.e. have both instances open in the desktop app). They would need to either log out / in to access each instance or they could dedicate the desktop app to their primary instance and keep a browser app (app.frontapp.com) open for the secondary instance.
We have a guide which provides a bit more information on this situation that may be helpful for you and your colleague: Multiple instances of Front
Cheers,
Cat