usar case com IN e NOT IN

Preciso de ajuda na query abaixo.

AND  CASE  WHEN A.CN9_CODOBJ <>'' THEN

	                           A.CN9_CODOBJ IN (SELECT   YP_CHAVE

	                               FROM            SYP010

	                               WHERE        (YP_TEXTO LIKE '%%') AND (D_E_L_E_T_ = ' '))

	                        ELSE

	                           A.CN9_CODOBJ  NOT IN SELECT        YP_CHAVE

	                               FROM            SYP010

	                               WHERE        (YP_TEXTO LIKE '%%') AND (D_E_L_E_T_ = ' '))

	                        END