Un-doing Two Sigs Required

We have a number of deposit accounts that were opened where the accountholder desired to have two signatures required for withdrawals. As this has become burdensome for bank staff to verify the incoming clearing checks, we would like to eliminate this requirement. For the existing account holders, what, if any, notification is required? The account agreements on file currently state "Except as otherwise provided by law or other documents, each of the undersigned is authorized to make withdrawals from the account, provided the required number of signatures indicated above is satisfied." The number of signatures above on the signature card states 2.