Except as otherwise provided in this part, and irrespective of the terms of any contract or other commitment, whether or not the facility has been designated for emergency use in accordance with section 3 of this part:

(a) No person shall transfer, and no person shall accept transfer of any port facility unless such transfer has been approved by the NSA.

(b) No person shall use any port facility for any purpose or use other than that for which it was being used on the day preceding the effective date of this part, unless such change in purpose or use has been approved by the NSA.

(c) No person shall change or alter the terms or conditions under which any port facility was being operated or used on the day preceding the effective date of this part, unless such change has been approved by the NSA: Provided, That this restriction shall not relate to the filing of tariffs with the Federal Maritime Commission as required by applicable law.