Hello KBoyajian, and welcome
Assuming you have a text report with a field defined as , and the field contains data with "," as a decimal separator, then you have two options. If this is the only numeric field in this report, then you can go to Options > Input and select Comma as the Decimal Character. This preference is saved in the model file and should not affect your other models and reports. Using this option, Monarch will look at the field, and if it is defined as Numeric, will assume the "," is the decimal separator. In the Table window, you'll then see the number as 2,345.67, because this formatting is determined by your Windows Regional Settings.
If your report data contains figures in multiple formats (say a USD amount in 2,345.67 and in the next column a EUR amount as 2.345,67) then the Options > Input method won't work, as Monarch uses the Decimal Character option for all the numeric fields it's trying to find in the report. But you can then handle it a different way, by defining as a Character field, not Numeric, and performing the conversion in the table.
From right to left, you are stripping out the "." as you don't need these, then replacing the "," with a ".", then converting the resulting string to a value.
Hope this helps,