Time indeed, that's just it, there is hardly any to undertake an election or another vote. Kept secret from all but the PM and trusted advisers, we now have a document which both May and the EU refuse to consider ammending published at the very last stages of the withdrawl process.
Given it is dislike by almost everybody it is unlikley to pass through parliament. The solution must be to call a snap election immediately after the vote. Labour will campaign on staying in the EU, the Conservatives on amending the current withdrawl agreement. If the Conservatives win, then it would be expedient to to request a deferal of article 50 for at least another 6 months to allow that process. If the EU refuse or changes cannot be agreed we leave without.