Custom Labels in editing phone contacts listings...deleting a custom label iPhone5c

In contacts, under phone listings, I created a custom label (rather than the listed choices such as mobile, home, work etc) and now I would like to delete the custom label, but cannot find a way to delete the new label I created from the custom label field. If I create multiple labels for one time use in one particular contact, I would like to remove that label from the field of choices, otherwise I will have a long list of choices to scroll through when I use the custom label field for future contacts. Can a custom label be deleted from the field of choices?