What is the process for extending a visa beyond the original four month validity?
The process is very simple. A consular officer can re-validate a K visa petition any number of times for additional periods of 4 months provided the officer concludes that the petitioner and beneficiary remain legally free to marry and continue to intend to marry each other within 90 days after admission into the United States. To have the petition re-validated send a written request to the Embassy that includes a statement of your intention to go forward with the marriage.