You will still be able to process the Feb 2015 pay. However, you need to make sure you change the salary to the correct amount.
1) Go to ePayroll > Payroll admin > Pay Information
2) Edit the employee’s pay under ‘Amount/Formula’ and click submit.
3) After that, process the pay run for the affected employee.
4) Remember to change the employee’s pay back to the original formula 'BasicPay' after you have successfully processed the pay run.