Repotting a Phal

[Shalva]

Hi Everyone
I could use some guidance in repotting a phal... it is flowering and I was told to wait to repot until it stops flowering BUT it is a relatively new plant that my husband bought me at the grocery store and the leaves are getting quite yellow..I knew it wasn't in a good pot... (plain old clay pot with no ventilation) and when I checked the potting medium it it mostly moss...actually it may be all moss... So considering that it is not looking healthy to me I am going to repot it and if it stops blooming then so be it at least it will be alive...

So I need to go and get potting medium... I am unsure as to what to use for a potting medium... bark or a blend??? and then I need some kind of instruction on how to repot this guy... I have never repotted myself and usually have had it done by someone else so instructions would be helpful... I would like to keep this plant healthy and not let it get weak.

thanks
s