These questions are very hard to answer without knowing a lot about your situation and the specific type of company pension you have.
There is nothing that will reduce your CPP disability cheque; however, sometime other payors can reduce their payment based on what you are getting from CPP disability.
Assuming it is not a disability pension from your work, then generally speaking there will be no impact on your CPP disability. You can get a full CPP disability payment and your pension payment, unless the pension payment is also for disability.