Redirect Webmail from one url to another with proxy

[1inux]

Hi,

i had to change the subdomain from zimbra 8.6 with nginx proxy from xyz.example.org to abc.example.org.
How can i do this?

zimbraDefaultDomainName: example.com
zimbraLogHostname: mx1.example.com
zimbraNotebookAccount: wiki@mx1.example.com
zimbraPublicServiceHostname: xyz.example.com
zimbraReverseProxyAvailableLookupTargets: mx1.example.com
zimbraReverseProxyUpstreamEwsServers: mx1.example.com
zimbraReverseProxyUpstreamLoginServers: mx1.example.com

Thanks for you help?
Jan