Joint tenants to Tenants in common

Hi, I and my wife made the Sev application and the application was completed  and the register updated.  Now, we need to change from joint tenants to tenants in common 50%to50% share, what form(s) do we need to fill and any fee for the change?

Thank you 

Hi Kevin - form SEV severs the joint tenancy and does change you from joint tenants to tenants in common 
If you mean you want to apply to cancel the form A restriction and become joint tenants again then our online guidance explains what's needed
Joint property ownership: Overview - GOV.UK

Hi Adam

It is exactly what I want to do -- from joint tenants to tenants in common. Happy not to fill any forms.

Appreciate for your help.