Changing Keyframe Values in the Animation Editor

You can change keyframe values in the Curves or Dope Sheet of the Animation editor.

To change keyframe values:

In the Animation editor, select the channel with the keyframes to edit.
Click Frame to view the channel.
From the Tools drop-down, choose Select.
Select the keyframes. To select multiple keyframes, Ctrl+drag to create a rectangular selection.

Note: To select keyframes in only the selected channel, Ctrl+F+drag creates a rectangular selection around the keyframes you select.
Drag the keyframes to the new values. Press Alt to snap the frame value (vertical axis) to the nearest integer. Press Ctrl+Alt to snap to the nearest multiple of ten.

Note: Enable Track Snap on the Filter tab to snap keyframes to frames (not in-between frames). Or, press Alt+Z to snap when Track Snap is disabled.

To set a specific value for a keyframe in the Animation editor:

Select the Channel that has the keyframe you want to change.
Set the positioner to the frame where the keyframe is located.
Click the value next to the channel name and enter a new value in the calculator. Or click the number and drag to change its value gesturally.