SELECT T1.date_of_enrolment ,  T1.date_of_completion FROM Student_Course_Enrolment AS T1 JOIN Students AS T2 ON T1.student_id  =  T2.student_id WHERE T2.personal_name  =  "Karson"
List the dates of enrollment and completion of the student with personal name "Karson".
[Schema (values) (types)]: | e_learning |  Course_Authors_and_Tutors : author_id (text) , author_tutor_atb (number) , login_name (text) , password (text) , personal_name (text) , middle_name (text) , family_name (text) , gender_mf (text) , address_line_1 (text) | Students : student_id (text) , date_of_registration (number) , date_of_latest_logon (text) , login_name (text) , password (text) , personal_name (text) , middle_name (text) , family_name (text) | Subjects : subject_id (text) , subject_name (number) | Courses : course_id (text) , author_id (number) , subject_id (text) , course_name (text) , course_description (text) | Student_Course_Enrolment : registration_id (text) , student_id (number) , course_id (text) , date_of_enrolment (text) , date_of_completion (text) | Student_Tests_Taken : registration_id (text) , date_test_taken (number) , test_result (text);