Generally, the Illinois Department of Revenue follows the IRS guidelines for verifying business income and expenses. The Governor's Office of Management and Budget must approve all out of State travel requests, even if there is no cost to the State of Illinois.Per diem supplements the cost of meals. Receipts are not required to receive this per diem allowance. Expenses paid in cash are not reimbursable without receipt. REQUESTOR. Receipts are not required to receive this per diem allowance. If they lose a receipt, the expense can't be submitted and reimbursed. Now the employee is paying for business travel with personal money. . Copies of itemized receipts for all expenses; and. (c). If a receipt is lost or does not exist, the Requester needs to complete the.