ER provider migration

Hi Community,

One of the customer has a setup that they’re using MPLS SD1 provider who is providing ER services to handle the workload.

Goal is to migrate Express route provider from MPLS SD1 to some other provider and decommission the current one. Looking for the best way to keep a co-existence wherein we can have two ERs on the same Virtual Network Gateway during the migration.

Questions:

1. Is it possible to easily keep and manage the routing between the two ERs? If not any other best practices?

2. Will there be any impacts/implications etc?

Any guidance would be of great help. Many thanks in advance.