Change Employment Model From two tier to 3 tier

Hello Everyone,

We have a requirement where we are looking at moving from two tier to 3 tier employment model. Reason being for few legislation employees can have multiple agreements and we want to have multiple open end dated assignments and contracts. Right now, we are under 2 Tier - Single Contract - Single Assignment employment model. Since this not applicable for all countries, we are looking at changing employment model at Legal Employer Level rather than at enterprise level.

We need help in understanding what will be impact on existing data from both UI and back-end perspective. We would highly appreciate any inputs or any help on this.