Three steps... First use the PMT function to calculate the monthly payment
based on the initial terms: =PMT(5%/12,36,-100000) (if the annual rate is
5%, for example).
Second, use the PV function to calculate the balance when there are 32
months remaining: =PV(5%/12,32,x), where x is the result of the PMT function
Third, use another PMT function to calculate the monthly payment based on
that balance and the new rate: =PMT(4.5%/12,32,y) (if the annual rate is
4.5%, and y is the result of the PV function).
This could all go into a single formula if you prefer. But it would be
harder to see the logic.

"Pule" wrote:

A loan amount of 100 000 to be repayed over 36 months, interest rate
changes(reduces) after 4 moths and 12 days
How do i calculate the repayment for month 5 and the remaining 31 months?