remove read-only domain controller from active directory

Dear forum,

my company have many brand and currently we installed Domain Controller at head office and RODC at brand site.

and we want to centralize our active directory and remove  RODC.

Please help me out to remove RODC role without affecting the server production environment. Is there is a way to perform it?

I am using windows server 2012 R2. RODC is in forest environment.

Thanks !