The phrase "interim basis" refers to something that is being done temporarily or for a short period of time until a permanent solution or decision is made. Full definition
Lyons is named to administer diocese / / Former Sacred Heart priest is elevated on interim basis following death of Bishop Dattilo (artobserved.com)
However, as they come to appreciate the full timescale for reaching trading agreements with the United States, China, Japan, India etc., which can not even be started until after we have left the EU, others may well come to see the EEA as a very sensible interim base from which to negotiate them. (blog.politics.ox.ac.uk)
Managed personnel and inventory on interim basis, scouted and assessed new employees, trained new mechanics. (jobhero.com)