increasing the year in a column

bit of a novice and also on a mac, i hope the xlsx is good.

this is the local legion membership list, columns J and K show branch and club joining date ( should be same but can differ )

I want to upload data to epos to give current members 10% off beer ( good hey )

How do i alter "J" from 11/02/1994 to 11/02/2020

then column "K" to be expiry date 12 months on 11/02/2021