If you want change your loan installment for a period then you can use "Change Instalment" button on the loan record.

Steps to be followed -
1. Enter the revised instalment amount

2. Enter Up to month - this is the month up to which your loan would be recovered as per the requested instalment
3. Click on "Submit for Approval", the request will go for approval as per the workflow

After the up to month goes by the EMI will revert back to its old value.

Note - Indian payroll rules allow companies to pay a loan at a subsidized interest rate but it then attracts a "perquisite tax". Such loans are classified as "With Perq" loans. Instalment cannot be changed for these loans.