Respected sir,
I am working in Health Department. I am maintaining my Record . I want to auto up to date the given value.

example --
field1=St date
field2=1st follow up
field3=2nd follow up
filed4=end follow up

1st follow up = St date+2months
2nd follow up= St date +4months
end follow up= St date+6 months.....
When I will put my St date in filed1.I need...