Dear Mr. Ahmed - Good Morning,
If you incorporate one clause in the appointment letter itself, it takes care of the same. You need to design a SOP for the same. The clause in the appointment letter may be like "during the period of your service with the company, you may be transferred to any of the offices/centers/units/divisions/departments/sections of the company or its associate companies which are existing or becoming part of the company in India or abroad, protecting the compensation package and allowances drawn in the current location/assignment.
The Heads of the department's commitment/involvement/ownership is very important in these types of assignments; hence, it is better to call for a meeting, obtain their inputs/viewpoints, prepare the minutes of the meeting, get it signed by every participant, submit it to the management for approval, and implement.
I believe that you are clear on the process.
Thanks and regards - Kameswarao