The Situation
An instructor who allows students to submit multiple attempts for assignments must enter a score in order to remove the attempt from Needs Grading.
The Expectation
Instructors may have students submit errant attempts (such as forgetting to attach a file), or a draft version of the assignment. In the case of the errant attempt, the instructor may just want to remove it from Needs Grading; for draft version of an assignment, the instructor may want to comment on the draft, but not necessarily enter a score.
Blackboard Learn's method
Blackboard Learn provides a couple of different methods for removing previous attempts from Needs Grading.
Grade a draft attempt:
1) From Needs Grading, click on the student attempt for grading.
2) You could enter 0 or other score and include formative feedback to the student in the Feedback area.