To be able to add or remove dialable statuses (dispositions), follow the steps from your main dashboard:
Go to Campaigns
Campaign List
Use the search box to find the campaign
Select
General Settings
Scroll down to Dialable statuses
Add/remove the status(es) that you want to be dialed again
Save Changes
Please note that only the statuses/dispositions that are added in the Dialable Statuses section from the General Settings of a campaign will be called again by the dialer.