Q.Transplanting my sago
Is it possible to dig up my sago? How and when is the best time?

Yes, it is possible to dig up a sago palm. It is best to transplant in spring before the advent of warm weather and before the plant starts growing new leaves. Hopefully your sago isn't too large and heavy otherwise you're going to need to enlist some help!
This website will give you step by step instructions on how to transplant your palm:
https://www.gardeningknowhow.com/ornamental/trees/sago-palm/transplanting-sago-palms.htm