automatically re-number when not deleting rows

Good day everyone!
I have a list of jobs to do in 1 column. In column 2 is the priority of the job. As a job is finished I want to delete the priority next to it and have the priority numbers re-number themselves (2 becomes 1, 3 becomes 2, etc.). These jobs are ongoing, so at some point I would want to go back to the original #1 and call it priority 6, so deleting jobs altogether is not an option, thus taking out the (row-1) ideas.
Any ideas on how I can set the priorities up to re number.

The list is not in order vertically because the priorities are not always the same.

Thanks for the help!

Thanks for the title change

Im not sure that this can be done with a regular formula.