How to call another section repeatly and pass in new data selection each time?

I have an existing custom UBE and it has one section called A. It uses the below commands in its Initialize Section because there are additional data selection that users will enter when they run this UBE and it does all the work in the Do Section

Set Selection Append Flag( <Yes>)

Set User Selection(BC Date - For G/L (and Voucher) - Julian (F0911)(DGJ),  <Less Than or Equal To>, PO Ending GL Date,  <And>)

Set User Selection(BC Date - For G/L (and Voucher) - Julian (F0911)(DGJ),  <Greater Than or Equal To>, PO Beginning GL Date, <And>)