she cant - the speaker has already ruled there cant be a 3rd vote unless there are substantial changes to the deal that has been rejected twice
she can "ask" for an extension as long as she wants- its the EU who decides if she is gonna get it
(she has asked for a 3 month extension)
NOW put yourself in EU shoes
what do you see?- there is only 1 deal on the table - After 4 months arguing the UK parliament has rejected it twice both by huge majorities (the 1st the largest a government has ever suffered - the 2nd the 4th largest)
Throught the last 6 months the PM has repeatedly said she will make sure the UK leaves 29th march
She then comes to you and asks for a 3 month extension so she can get the deal through parliament (the same deal thats been rejected twice)
Now you start thinking - how the f//k is she gonna get a deal through parliament in 3 months when parliament has already rejected it twice, looked it over the last 3 months-and aint gonna get a 3rd bite of the
So what difference is another 3 months delay gonna make?)