Hello Pooja,
ChaRM default process is for 3 tier landscape and the entire workflow is for 3 tier landscape only in standard.
incase if this is temporary you have to act differently but if you need to have 4 tier you have to adapt charm for 4 tier then
ofcourse we can support complex landscapes like 4,5 or 6 tier landscape etc but you need to do lot many changes to adapt ChaRM for the same using configuration without development.
But yes may be development as per scenario or complex requirement arises.
e.g check below blog of dolores
Change Request Management scenario: Usual questions and known errors
you would need to define STMS as per SAP recommendation check below note
1531565 - Four System Landscape in Change Request Management
there are some bugs as well 4 system related to check for notes like below or relevant as per your solman release
1690362 - ChaRM: pass correction to test trigger import to pre-prd sys
there are more problems if you have 3 or 4 or 5 tier systems landscape all together
2226397 - ChaRM: preliminary import is not triggered for project with uneven transport tracks
you need to define a new status and action ...check below for how to
hope this helps
Thanks
Prakhar