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url: /flow/guide/scripting-reference/functions/program-control.md
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# Program Control

You can modify the [Program Flow](/flow/guide/scripting-reference/program-flow) through the use of these functions.

Modifying Program Flow is essential when mapping data definitions that have differing structures. For example if the source data definition is a list of order lines, and this need to be mapped to a data definition with order header/order line structure you will need to call [ProcessMasterRecord](/flow/guide/scripting-reference/functions/program-control/processmasterrecord)when you need to create a new header record in the destination.

The following Program Control functions are available.