Determine the spot and 12-month forward exchange rates, and determine any change in the ROS repatriated in 12 months based on exchange rates versus the current forecast. 

The spot exchange rate is the current market rate at which one currency can be exchanged for another. To determine this, you would need to know the currency pair you are interested in (e.g. USD/EUR) and then look up their respective rates on an online currency converter or a forex trading platform. The 12-month forward exchange rate, meanwhile, reflects the expected future value of a currency compared to its spot rate. This can be calculated by taking the current spot exchange rate plus an interest factor that takes into account any difference between interest rates in two countries as well as expectations about how those rates may change over time.

Given these two figures, it would then be possible to calculate any change in ROS repatriated in 12 months based on exchange rates versus the current forecast by comparing the expected future amounts with those previously estimated; if there has been a significant increase or decrease then this could impact both short-term planning decisions as well as long-term investment strategies depending on whether such changes were predicted or not.