What is the impact on existing routines if we create expert routine?

Automatically existing routines will be deleted or deactive. 

We have following types of routines in BI 7. 

Start Routine:

The start routine is run for each data package at the start of the transformation. The start routine has a table in the format of the source structure as input and output parameters. It is used to perform preliminary calculations and store these in a global data structure or in a table. This structure or table can be accessed from other routines. You can modify or delete data in the data package.

Routine for Key Figures or Characteristics:

This routine is available as a rule type; you can define the routine as a transformation rule for a key figure or a characteristic. The input and output values depend on the selected field in the transformation rule. 

End Routine:

An end routine is a routine with a table in the target structure format as input and output parameters. You can use an end routine to post process data after transformation on a package-by-package basis. For example, you can delete records that are not to be updated, or perform data checks.

Expert Routine:

This type of routine is only intended for use in special cases. You can use the expert routine if there are not sufficient functions to perform a transformation. The expert routine should be used as an interim solution until the necessary functions are available in the standard routine.