You can only edit a campaign if it is Inactive.

If your campaign is Active/ Paused/ Ended, it’s not possible to modify or change the settings.

If you would like to change the settings for an Active campaign, you’d need to delete it and create it again.

NOTE: If you delete an Active campaign, the cost of all the unsent SMS in this campaign will be refunded to your account balance automatically.

If the Active campaign has already started sending SMS, you need to pause the campaign and export the unsent contacts to create a new campaign with the correct settings.