Reassign credit card transactions from Corporate Travel office to employees

We have a several employees with occasional need (one to three times per year) to travel for job-related events.  Their travel needs are not consistent enough to warrant issuing a corporate credit card to the employee.  Our internal audit group has identified the use of personal cards by these employees to purchase travel tickets on their own behalf as a potential internal control issue.  A suggested alternative is to have the corporate travel office purchase the tickets on their behalf. Ideally, we want the employees concerned to apply the credit card transactions for the tickets purchased by the corporate travel office to