A private letter ruling (PLR), is a written statement issued to a taxpayer that interprets and applies tax laws to the taxpayer's represented set of facts. A PLR is issued in response to a written request submitted by a taxpayer. A PLR may not be relied on as precedent by other taxpayers.
Specifically to this PLR - see Hawaii Revised Statutes Chapter 237D -www6.hawaii.gov/tax/hrs/hrs_237d.pdf
§237D-3 Exemptions. This chapter shall not apply to:
(4) Living accommodations for persons in the military on permanent duty assignment to Hawaii, including the furnishing of transient accommodations to those military personnel who receive temporary lodging allowances while seeking accommodations in Hawaii or while awaiting reassignment to new duty stations outside the State;
In the PLR - see page 4 - http://www6.hawaii.gov/tax/ltr_rules/ltr12/jlh_ltr12-04.pdf
The proof necessary for Taxpayer to establish that the gross rental income it received
from a military person is exempt under HRS § 237D-3(4) is found in Hawaii Administrative Rules (HAR) section 18-237D-3-01(d)(1), which provides:
To qualify for an exemption under [HRS § 237D-3(4) and HAR § 18-237D-3-01(a)(4)] the operator shall require that the person in the military on permanent duty assignment present the following at the time of check-in:
(A) An identification card with a serial number which verifies the person's military status; and
(B) A copy of the orders prepared by the military organization verifying the period for which the temporary lodging allowance is received.
The operator shall maintain copies of documents supporting any claim for an exemption under this paragraph for three years.
That is what needed to to apply for the Exemption outlined in the PLR 2012-04.