To batch update funds in Alma:
Do an advanced PO Line search for the PO Lines for which you want to change the funds. Apply filters as needed. Once you have the results, in the upper right hand corner click "Create Logical Set."
Go to Admin => Manage Sets and itemize the set. (Not sure this is required, but it worked.)
Go to Admin => Run a Job and search for the job "Update PO Lines transactions."
Check the box next to "Fund," select the fund you want to change to, and be sure to enter 100 in the Percent box.
Continue and run the job.