You will need to start by setting up an account with the new provider. Once you have the account created, you will need to ask them for their "MX records". Once you have the MX records, you will log into your account on www.homestead.com and click the Domains link on the left side of the screen. On the domain manager screen you will see a link that says "advanced dns settings". In this area, you will remove Homesteads MX records and replace them with the other companies.