a) Get into the file path /wp-content/plugins/designthemes-pregnancy-addon/custom-post-types/dt-procedure-post-type.php at line number 64(approx) add the slug name there.
b) After that do the following changes,
i) Go to Wp-admin (Dashboard) / Settings / Permalinks
ii) Set the permalink structure into “Default” and save changes.
iii) Again change it as “Post Name” structure and update then.