When the workflow trigger event occurs the trigger will check that any required conditions are met, and if met the "clear-expiration" action clears the expiration date.
"clear-expiration"
An existing expiration period can be removed using "clear-expiration".
If adding the JSON trigger using workflow builder there is no need to include the opening "triggers": JSON markup notation, since it will be added by workflow builder.
A new expiration date can be added using the "set-expiration" trigger action.