43 CFR §3430.4-2

1. (a)If the applicant for a preference right lease has submitted timely, some, but not all of the information required in § 3430.4-1 of this title, the authorized officer shall request additional information and shall specify the information required.
2. (b)The applicant shall submit any requested additional information within 60 days of the receipt of the request. The authorized officer may grant one 60-day extension if the applicant files a written request within the first 60-day period.