None of which will be big enough to change the minds of most Brexiteer MPs. They could, however, reduce the size of the rebellion and make the two-ball strategy again feasible.
What happens if MPs do not exceed it?
The original plan, once it became clear that the government would lose the vote on the first attempt, was to try again a few days later. The expectation was that Mrs. May would try to negotiate some concessions from the EU, while the market turmoil would frighten the MPs and make them rethink. Although, with operators well aware of the plan and therefore "pricing", the chances of a major change in the markets seemed to be reduced.
While "renegotiation" will now take place before the vote, Downing Street may still need more than one attempt to get it through Parliament.
In the period between a first and a second attempt to pass the agreement, Labor would probably try to force a general election. This would be very difficult because of the Fixed Term Parliament Act and would require conservative MPs to help overthrow one's government.
If and when this attempt fails, Labor may try to get a vote for a second referendum. This would still require the support of conservative parliamentarians, but it would probably be easier than forcing general elections. These efforts have recently been reinforced by the European Court of Justice's ruling that the United Kingdom can unilaterally revoke Article 50.