You have to be in single user mode to be able to adjust stock on hand. Can I suggest that SOH can be adjusted directly in the "Edit item" section rather then having to wait for employees to log and out and having to scroll through your whole item list to adjust a couple of items.
May not be technically possible due to database, however we will leave as an open idea.
Note:
Another way to adjust stock is to use a zero dollar sales receipt. Many retailers do this to write-off soiled stock. This can be done in multi-user mode and often the business will create a custom template to remove fields not required.