What are the prior procedures for persons making zero rated supplies to claim refund of taxes paid in relation to supply of goods or services under bond or Letter of Undertaking

Any registered person availing the option to make a zero rated supply of goods or services without payment of integrated tax shall furnish a bond or a Letter of Undertaking in FORM GST RFD-11 prior to execution of such supply.

(ICAI FAQ PUBLICATIONS 06-09-2017 REFUNDS: FAQ NO. 24)