How to create Process chain for Aggregate for Master data

Hello friends,

I created Aggregates on Navigational Attributes.

Now they are working fine, but i need to know that how shall i create the Roll up for Aggregates on Navigational Attributes.

The point is the master data changes frequently a lot of time for e.g. for 0customer etc.....

So if any one can send me the step by step documents so as to know how to roll up the Aggregates for Navigation attributes or for aggregates created on Master data....

How to create process chains for the same ?????????

Because if master data changes, then rolling up the aggregates straight forward will not help.

So we need to write a process chain so that it deactivates the aggregate and reactivate again and fill up again..........

If i mis interpreted something please rectify it.......

Please advise