Is it possible to submit new GRE scores after having applied to an acadmic program? I intend on taking the GRE but I haven't had the time to study much and so now I feel I am facing the option of either


Taking the GRE anyway, most likely getting very unimpressive scores and applying to academic programs with these scores, or
Cutting my losses and applying for programs the next time they announce applications (which, in some cases, is a year from now).


Is it possible to apply with my first scores as some sort of "provisional" score and inform them that I will be re-taking the rest soon? How much does a "bad first time, better second time" affect how admissions reviewers see applicants? In the case that extra background information would be helpful, I am a non-traditional student who already has a (short) record of research experience.
Honestly, the GRE scores are perhaps the most useless part of the application record. Good scores tell me that someone speaks English well, and is capable of basic mathematics. A bad score could just be a signpost of having a bad day, or perhaps some issues with English that don't necessarily translate into being a bad student or a bad researcher. (Just about the only thing GRE scores tend to correlate with in grad school is the performance in first-year classes!)

If you do have replacement scores, you can definitely send them to grad schools. They'll be considered, but they're not likely to sway a decision (unless the school has a minimum cutoff—which is possible for international students).