You can use the Interpret Footage command to change the frame rate that Adobe Premiere Pro assumes for a clip. Changing the frame rate changes the original duration proportionally. For example, if you set a 10‑second, 24‑fps clip to 48 fps, it becomes half as long, with a new duration of 5 seconds. Be aware that a clip’s frame rate is reconciled with the project’s frame rate. For example, if you change a 24‑fps clip to 48 fps and it’s used in a 24‑fps project, the project can display only every other frame of the clip.

You can also change clip speed and duration by choosing the Clip > Speed command for a clip selected in the Timeline panel. However, such a change affects only that clip instance in the Timeline panel. Using the Interpret Footage command changes how a file is interpreted throughout a project.