受取人様が保管先のUSPSに荷物の保管依頼と受取の日を電話で伝えていただけないでしょうか?
それが一番確実な方法だと思います。
さらなるご協力に本当に感謝します。
Will you contact USPS and ask them to keep the product for you and tell them when you would like to receive?
I think that is the surest way.
I truly appreciate your further cooperation.