The Customize Approvals section labels options of the Approval Global Configuration screen allow renaming header labels of the Approvals section displayed on the issue screen.
By default the labels are: Comment, Approval Name, Detail, Request Notification and Action.
The screenshots below show, on the right, the Approvals Section displayed on an issue based on the Customize Approvals Section Labels settings on the left.
Approval Global Configuration screen
JIRA issue screen