You can offset a curve or a group of keyframes on the horizontal or vertical axis. The offset value is set using the Curve Value field.
(a) Curve Functions field (b) Curve Value field
A negative value offsets the channel or group of keyframes to the left (Translate X) or down (Translate Y). A positive value offsets to the right (Translate X) or up (Translate Y). The value in the Curve Value field produced by the drag returns to zero after release.
The selected channel or keyframes are offset. The coordinates of each selected keyframe, relative to each other, remain unchanged. Translating along the Y-axis is only visible in the Animation Curve window.