Off white color combination for wall
Pink is Red+White and off-white is Yellow+White.
So essentially what you need to do is turn Red into Yellow which is not possible for additive colour scheme because Red and Yellow are primary colours.
Only way to achieve this will be to paint Pink wall with lots of White and then add little bit Yellow in it.
But still depending on the brightness of Pink, you will get shades of Orange instead of off-white.