Not in your current sequence. You need to create a new sequence with the proper pixel dimensions or create a new project.
Thanks for your quick reply.
Is there any way to copy all the edits into the higher res Sequence? Maybe open in AE, change the res, and export back to Premiere?
There is no draft resolution presets in premiere. There is only the dynamic preview quality settings that can be adjusted in the source and program monitor.
You can copy all of your clips and paste them into a sequence that is the proper size, then make adjustments to individual media assets accordingly. Or you can drop your "draft sequence" in a proper format sequence and see what happens, it won't be good I'm afraid.
In the current release of Creative Cloud, you can change the resolution of a project after you've put assets on the timeline by choosing "Sequence" --> "Sequence Settings" and adjusting the frame size to the desired resolution. Note that this will not resize your assets to the new frame size. The "Scale" tool under "Effect Controls" --> "fx" (dropdown) is useful for quickly resizing, though in a project like the one mentioned above at 864 x 486 it is unlikely those assets would scale well on a frame of '1080p' (1920*1080), for example.