How you can make an upper complete denture to patient has deep undercut labially and buccally?

It depends on the amount of undercut if requires correct surgically or block the undercut during the procedure. Regards

First of all if the undercuts are very deep, one should consider reducing them surgically. Alternative may be to construct denture in flexible material (Valplast) by taking impression in elastic material. 

I think this could be done by lowering the flanges a little bit and trying to emphasis the post dam while taking the impression to compansate the retention hoping it works fine. good luck