P.R. Laws Ap. tit. 32A, § III, Rule 41.4
(a) Meetings. — When a reference is made, the clerk shall forthwith furnish the master with a copy of the order of reference. Upon receipt thereof, unless the order of reference otherwise provides, the master shall forthwith notify the parties or their attorneys of the time and place of the first meeting to be held within twenty (20) days after the date of the order of the court. It shall be the duty of the master to proceed with all reasonable diligence. Any party, on notice to the other parties and master, may apply to the court for an order requiring the master to expedite the proceedings and to submit his report. If a party fails to appear at the time and place appointed, the master may proceed ex parte or, in his discretion, adjourn the proceedings to a future day, giving notice to the absent party of the adjournment.
(b) Witnesses. — The parties may procure the attendance of witnesses before the master by the issuance and service of subpoenas as provided in Rule 40. If a witness fails to appear or give evidence, without adequate excuse, he may be punished for contempt and be subjected to the consequences, penalties and remedies provided in Rules 34 and 40.
(c) Statement of accounts. — When matters of accounts are in issue before the master, he may prescribe the form in which the accounts shall be submitted and in any proper case may require or receive in evidence a statement by a public accountant or a certified public accountant who is called as a witness. Upon objection of a party to any of the items thus submitted or upon a showing that the form of statement is insufficient, the master may require a different form of statement to be furnished, or the account or specific items thereof to be proved by oral examination or upon written interrogatories or in such other manner as he directs.