By editing your approval or decline message you are changing the email that members receive when you manage your requests by pressing the Approve and Decline buttons.
Please note that when you edit the Approval/Decline DEFAULT email, the new edited version becomes the default that is used for all future approvals or declines (until you edit it again). The default Approval/Decline emails are across all members and all titles that do not have a customized message.
You can add a title-specific Approval/Decline email from the title record which will only send to those members you approve or decline for a certain title. If there is no title-specific email set, the member will receive your default email.