You can't copy the pieces of a module. However, you can alt/option click on an element and then either place a new instance of the element for a library part or as in the case of a wall, start to draw a new one.
If, on the other hand you are wanting to change the module with the new element then select all the module elements and either overwrite the module or create a new one.
HTH
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"