you can do it in a new blank drawing.
"Say your drawing template is set to imperial 1/4" scale & you want to use this for your output but have a sketch with dim's called out in Metric. Continue with your normal drawing template, when you input values from the sketch just (eg 3655) just type this value into your OBJECT INFO PALLET but be sure to add mm at the end (ie 3655mm) and VW will do the math for you. Your drawing will be in imperial, but the values will have been converted. This also works if the values were noted as decimal Meters (eg 3.655) just type a M after this value (ie 3.655M)."
thanks for this, Jim