The article outlines the steps to edit or delete sizes. Please note a Size can not be deleted once linked to a Job.
FOLLOW STEPS BELOW:
1. In the Navigation Pane, go to Administration -> Lookups -> Sizes
2. To edit a Size, select the Size Name/Code and fill in new details
3. To delete a Size, select the Size and then press the "X" Icon
NB. For a quick tutorial watch below