How to change the system role in Solman7.1

Hi,

I am new in Solution Manager.so i want your valuable advice on my issue.

Actually we are using Solman7.1 SP10,The issue is that DE1 system is assign as QAS and the client requirement is to change the system role and make as sandbox(Evaluation ) or unit test system.

So,My question are:

1) what is the pre step and post step activities?

2) How can i change the system role with full steps?

3)The project is already running so it is possible to change the system role and no any effect on the project?

4)Is there any changes in transport route also?

Regards,

Abhinash