I am attempting to append a feature layer into another empty feature layer of the same structure in ModelBuilder. I get an 000572 error which apparently means the source and the output of the append cannot be the same, and that the solution is to change the output name. I do this in modelbuilder and it automatically changes the source target name. If I run append from ArcMap directly I can easily execute the append of the blank target datset with the populated source datset with no error messages. I am using ArcGIS 10.4 Any help would be greatly appreciated.