Edit Recoverable Tax code Combination

Hello Everyone ,

We are on R12.0.6 , We want to edit Recoverable tax code combination, in Invoice tax distribution line, Currently its greyed out and does not allow to edit , please refer screen shot attached

Tax lines are added manually by going into tax details forms and selecting tax regime and tax and all other details from LOV .

Following Allow options are setup in eBTax setup

Tax Regimes

Allow Tax Recovery - Yes

Allow Override and Entry of Inclusive Tax Lines -Yes

Taxes 

Allow Override and Entry of Inclusive Tax Lines -Yes

Allow Tax Rounding Override - Yes

Allow Override for Calculated Tax Lines- Yes