Legal Question in Wills and Trusts in Georgia

Sure.

If you continued to act under the assumption that you still had the power, you wouldn't be liable for any acts taken properly until you received notice. Moreover, those who transacted with you would not be liable to the grantor before they received notice of the change in the power.

In general, it is to the best interest of the grantor to inform the grantee when s/he is changing the power. Indeed, under the power of attorney, you probably signed off as the grantee of the power. Moreover, the document granting the power usually states that the power remains in effect until the grantee receives notice of the modification/revocation.