Riot assigns the region based on your location and hence, you can simply create a new ID by using a VPN and then enjoy the game permanently from that region. To do so, follow these steps:
1. By using any VPN you trust, connect to the region from which you want to play.
2. Create a new ID on Riot website
3. Once a new ID is created, you can switch off the VPN and just log in through Valorant and enjoy the game from a different location.
By using this method, what you essentially do is just create a new ID in a new region hence you can play in those respective servers. Also, VPN is only required once, and hence this is the simplest method to change the region by creating a completely new ID. Log in with this new region-specific id to play with your abroad friends.