Track Stretching Mode
This mode is used for adjusting Interpolation Intervals.
Track Stretching Mode can be enabled by selecting Track stretching mode from the Edit menu, or by pressing Ctrl + T
For this mode to work correctly, you have to previously select an interval on the Timeline
Once you enable Track Stretching Mode, the interval you've selected on the Timeline will be marked with a yellow border
Timeline in the Track Stretching Mode
Now you can drag the last frame of the interval to adjust its length.
An example of using Track Stretching Mode to change the length of an animation
When an interval is edited under this mode, every selected key frame moves to keep its position in relation to the length of the interval. This way you can edit the length of a movement while keeping its structure.
Note: Type of interpolation on the adjusted interval will be changed to Fixed
To exit Track Stretching Mode without making adjustments to the selected interval, simply click anywhere in the program window