Writing code that run across different regions

I am working on enhancing a Spring boot Microservice that is developed for the Consumer registration in the UK region. The service domain model and validation logic is coded based on the consumer registration details in UK. The Micro service accepts UI to provide Consumer's name, address etc and run some validation on that before registering consumer with system.

I have to enhance this service to run for the US region. The existing domain model won't fit for the US. In UK, consumer's address format is different than US. Also, there is no SSN in the UK region. There are different address verification systems in UK vs US.

So overall, I cannot use the same Micro service developed for US region. I wanted to ask, how do we develop Services that works across different geographies considering differences in the domain model and requirement for integration with different back-end systems (address validation for example).