Migrate entire Environment data from one environment to another environment

If it's a Cloud environment, you could potentially ask Appian Support to look into doing an environment clone (copying an existing environment into, preferably, a brand new one).  I don't believe they'll do this in a way that would overwrite an existing alternative environment, unless there were emergency reasons and loads of ownership sign-off (and even then maybe not).  Note that this might incur expensive one-time charges for the extra work involved (i'm not positive, just piecing together what I remember hearing in other places about this).  You'd need to ask them for the particulars / options / logistics.