To convert an item to another measurement, use the command item/update_measure_units:
svc=item/update_measure_units¶ms={"itemId":<long>, "type":<uint>, "flags":<uint>}
| Name | Description | 
|---|---|
| itemId | item ID | 
| type | target measurement (0 - metric,1 - U.S.,2 - imperial) | 
| flags | 0 - set measurement, 1 - convert values and set measurement | 
{} /* empty object if execution successful, if not - error code */