Brihat Parashara Hora Shastra
युञ्ज्यादुच्चादिगे खेटे फलं नीचादिगे त्यजेत् । एवं शुभाऽशुभं ज्ञात्वा जातकस्य फलं वदेत् ॥ १७॥
If a malefic is in the Bhava, reverse the process, i.e. add inauspicious effects and deduct auspicious effects. Similarly Drishtis and Balas. If a Grah is exalted, or with such a dignity, add auspicious effects and reduce inauspicious effects. For debilitation etc. it is converse.
english translation
yuJjyAduccAdige kheTe phalaM nIcAdige tyajet । evaM zubhA'zubhaM jJAtvA jAtakasya phalaM vadet ॥ 17॥
hk transliteration by Sanscript