In this case I believe the command you are looking for is redeploy
:
progress = redeploy('myAppName', appPath='new/path/to/file')
progress.getState()
If you run into errors, you may need to put the new ear file into the original location OR execute an undeploy first, then do a normal deploy.
Reference:
http://docs.oracle.com/cd/E13222_01/wls/docs92/config_scripting/reference.html#wp1024321
Another example:
http://zachxu.blogspot.com/2010/08/how-to-use-weblogic-wlst-to-redeploy.html