Changing an object account subsidiary number

Hi everyone,

Has any corporation ever needed to change the subsidiary account string in order to have it roll-up in reports under a different object heading account?  For example, we currently have subsidiary account number 95343 rolling up under heading account 95300, however we need it to change and roll up under 95100.  What's the risk in changing the sub account number? How did you deal with maintaining history of the old account?

I'm open to any other ideas on how to deal with this issue.

Thanks,

Cindy