Changing broadband supplier

Hi, simple question. Currently with Virgin, and contract is now up. Openreach have finally installed FTTP in my road and are taking installation orders, so I will be switching to BT or Sky in the next month (hopefully!).

So my question is, when it's all installed and new router up and running, is it just a case of plugging my Deco M4's into new router and will work as they did before? Or do I need to reset them and reinstall them? 
 

Thanks