Use Resize to change a clip's resolution, frame depth, and aspect ratio.

To access the Resize menu, use:
Timeline, then use Batch FX (See Creating ConnectFX).
This node accepts a front clip, and outputs a result.
You can also use Resize to pan and scan the destination image relative to the source. You can then select and animate the portion of the source clip that appears as the destination clip, and process to create the result image.