FX Transaction: One Currency to be Converted 
Function
When a transaction only involves one currency that needs to be converted, the system takes the rate notation for the currency pair from the leading/following currency table (TCURR).
If you want to change over a USD/DEM transaction, you enter EUR/USD in the leading currency table. This entry is used as the new notation for the currency pair. The system determines the transaction exchange rate (VTBFHAZU-KKURS).
If the spot rate and the swap rate also need to be calculated, this is done as follows: