Can you refile a provisional patent application?
Yes, it is possible to refile a provisional patent application. Refiling, however, does not mean that the application will be valid. The end result is that you will replace the earlier priority date of your first provisional application with the later priority date of your subsequent provisional. The biggest risks of a later priority date involve prior art and your own public disclosures which may limit your rights. So the real questions relate to whether or not you should refile a provisional, and what risks you take by refiling.
Risk of more prior art
A later priority date naturally allows more prior art that can be used against you. If you abandon your first provisional and refile eleven months later, for example, then eleven more months of additional prior art can be used against you.
Risk of public disclosures
You would also need to assess whether you’ve made any prior public disclosures that would make your first provisional priority date critical. The US has a 1-year grace period. It would be safe to assume that most foreign countries have zero grace period, so keeping the earliest priority date may be critical for foreign patent protection if you’ve had public disclosures since then.
Benefits of later priority date
Assuming the above risks are worth taking, then a later filing date offers the key benefit of buying more time – more time to make key decisions, and more to save money to follow through on those decisions. A greater investment will be require for the US nonprovisional application and for the PCT or any direct foreign applications.
A later priority date also provides you with a patent term that lasts a bit longer. A later provisional filing date, which does not count toward the 20-year term for a utility patent, enables a later filing date of the nonprovisional which would start the clock for counting the term.
Should you abandon your first provisional before refiling the same provisional patent application?
Yes, you should expressly abandon your first provisional patent application before refiling the same provisional especially if the subsequent provisional will be filed during a time period in which the first provisional may still have outstanding rights. When you intend to rely on the subsequent provisional only for priority and not the first provisional, Article 4C(4) of the Paris Convention states:
(4) A subsequent application concerning the same subject as a previous first application within the meaning of paragraph (2), above, filed in the same country of the Union. shall be considered as the first application, of which the filing date shall be the starting point of the period of priority, if, at the time of filing the subsequent application, the said previous application has been withdrawn, abandoned, or refused, without having been laid open to public inspection and without leaving any rights outstanding, and if it has not yet served as a basis for claiming a right of priority. The previous application may not thereafter serve as a basis for claiming a right of priority.Paris Convention for the Protection of Industrial Property
Of course, you would not want to abandon your first or any prior provisionals if your nonprovisional will ultimately claim priority to all pending provisionals.