Repeating GRE scores works out? weather the aggregation of the scores or best1?

hi friends,
i just took GRE at London, i got 750 in quants and 320 in vocab which is a very bad score, i wanna to resit for the exam, but my doubt is weather the new score will be an aggregation of two tests or the second test’ s highest score will be reported. no idea how it works. any one could suggest me please. i wanna to apply for phd. i must try to get more than 1300 at least to enter into some presatgeous universities.

thank you
pratap :idea: