Dropping column with foreign key Laravel error: General error: 1025 Error on rename

You can use this:

Schema::table('despatch_discrepancies', function (Blueprint $table) {
    $table->dropForeign(['pick_detail_id']);
    $table->dropColumn('pick_detail_id');
});

If you take a peak at dropForeign source, it will build the foreign key index name for you if you pass the column name as an array.