A device detracts fluid from a flow line into a repository for temporary storage and later use. Before an infusion set is changed, medication from the infusion set is detracted into the repository, where it is temporarily stored. Once the new infusion set is connected, medication is dispensed from the repository into the flow line of the new infusion set. The device thus reduces or eliminates waste of medication that was in the flow line of the infusion set, by saving the medication in the repository while the infusion set is being changed.