Clearing disc space

Dubbing VHS to DVD and overwriting to the last title thinking you have enough space left on the disc to dub the working VHS. Suddenly the dubbing stops and writes to disc. I still have a few minutes to be recorded, but a new title space is not displayed due to lack of time remaining on the disc. I am now left with an incomplete title and ideally would want to delete the used space to free up the title for a new overwrite. Is there a way to safely delete the incomplete VHS and retain the title for something requiring less time? This does not mean that the previously recorded material has been wasted, or has to be redone, but it is an irritating problem, as I now have some two hours vacant on the disc, but can't use it for something else. Is there a way to delete and free up the space for recording a title requiring fewer minutes? Thanks, Searcy