Employee is relocating to different country. What changes with an employer-of-record agreement?

Employee is relocating to different country. What changes with an employer-of-record agreement? One of our employees will be relocating to Germany, and we'd like to keep them in the same role rather than lose them or move them onto a contractor agreement. Since we don’t have a legal entity there, we’ve been looking at the employer-of-record route. We’ve had a few demos with Globalization Partners, and the setup seems fine, but I’d be interested to hear from anyone who has actually managed an employee this way. I’m also unsure how things like existing tenure are usually handled. If someone has already been with the company for several years, does that carry over in any meaningful way? Does the new employment agreement essentially govern notice periods, benefits, and similar terms? For anyone who has managed someone through an EOR, what would you make sure was clearly agreed upon before making the change?