Okla. Stat. tit. 12 § 1183
The garnishee may be examined by the judgment creditor in any manner prescribed by the Oklahoma Discovery Code. Discovery may commence at any time after the service of the garnishee summons. If the garnishee is a corporation, any principal officer thereof may be so examined. Within forty-five (45) days after the filing of the answer affidavit by the garnishee, the judgment creditor may commence discovery concerning any matter contained in the answer or germane to any liability on the garnishee's part to the principal defendant. A copy of the discovery request or notice of deposition and such statement shall be served upon the garnishee or the garnishee's attorney of record in the manner provided for service of summons. The garnishee within twenty (20) days of the date of service of a discovery request shall deliver by mail a copy to the judgment creditor or the judgment creditor's attorney of record, full and true answers to all discovery requests, verified by affidavit, in the manner prescribed by the Oklahoma Discovery Code.
Okla. Stat. tit. 12, § 1183