Yes, you may refile a provisional patent application as long as you have not publicly disclosed your invention and understand that you will not be able to take advantage of the previous provisional filing date.
Let’s get into the details:
A provisional patent application is a temporary filing that holds your spot in time based queue called the priority date, which, in case of provisional applications, is the filing date. This is the date the USPTO recognizes as your invention date. Anyone who came up with a similar idea as yours after your invention’s priority date will have inferior rights – in other words, they won’t be patent the exact idea of your invention, as disclosed.
Provisional patent applications are held in confidence at the USPTO. This means that unless you publicly disclose your invention, no one will know about its existence. So refiling a provisional application simply means discarding the previous application and filing a new one, and being awarded with a new priority date.
And this brings us to the main issue: since a refiled provisional application will now be awarded a new priority date, if anyone filed an application disclosing a similar invention after your first (original) provisional filing, but before the second (refiled) provisional filing, that person now holds superior rights over the invention than you.
Also keep in mind, statutorily, you have one year from publicly disclosing your invention to file a patent application. Thus, you may not be able to refile the provisional application if the refiling happens to be more than one year after your public disclosure. What constitutes as public disclosure is a complicated subject by itself and it is best that you contact your patent attorney before considering refiling the provisional application.
To summarize: Yes, you may refile a provisional application, but your invention’s priority date will change and your innovative rights may be affected.