Need to create Dynamic Varient

Hi,

Need to create Dynamic Varient

My Requirement is :

When the program runs on last day of the month, varient has to be set up to populate the

the File path as :

/PA1/Interfaces/FlatFiles/new_sales_history.txt

When the program runs on Working day + 1, then the other varient has to be set up to populate the File Path as :

/PA1/Interfaces/FlatFiles/sales_history.txt

Can anybody let me know how i can create Dynamic Varient...?

Any suggestions will be appreciated!

Regards,

Kittu