How to update the secondary Unit of measure for Existing Item in Product Information management

Summary:

As per the business new requirement need to update the secondary unit of measure and tracking Unit of measure at Item level. we can able to update the secondary Unit of measurs for new Item. but could not able to update existing Item.

Items Come in a bag of 500 caps. Have the same dimensions and packaging Use "Pack" as the Unit of Measure (UOM). 10011628 is exactly the same product (500 caps per bag). But its UOM is configured as "Each" instead of "Pack". so we want to Configure Multiple UOM Conversions.

Content (please ensure you mask any confidential information):

Need to update the secondary Unit of measure at Item level.