Bathtub Lift Chair How Do I Remove A Very Tight (lift Up Type) Bathtub Drain Cover?

How do i remove a very tight (lift up type) bathtub drain cover? - bathtub lift chair

I tried to clean up my bathtub and noticed the manhole cover was dirty. When he pulled the drain plug is released. Two of the 4 members of the participation of the Red Cross broke and now can not be printed from the Assembly. Insert the handle of the hook does not move the manhole cover at all. His firm. Could be due to the cement of the plumber? Please help.