In the Flow Sheet, you will first need to make sure that the functions are not checked (i.e. they should be greyed out). Then Right-click Edit Flow Sheet | select Function (so that it is highlighted in blue) | Right-click Delete | click OK. When you go back to the patient's Flow Sheet that item will no longer be there.
NOTE: If Delete is greyed out, this means that the function is currently checked (lit up in green) or was previously used on this flow sheet so it cannot be deleted. If so, you can Uncheck it instead to not use it.