47 CFR §1.1309

Applicants are permitted to amend their applications to reduce, minimize, or eliminate potential environmental problems. Amendments shall be made electronically. As a routine matter, an applicant will be permitted to amend its application within thirty (30) days after the Commission or the Bureau informs the applicant that the proposal will have a significant impact upon the quality of the human environment (see § 1.1308(c)). The period of thirty (30) days may be extended upon a showing of good cause.