To Keep a Particular Field as Optional in Acc Sequence - SAP SD Pricing

Hello All,

Need your guidance on below query.

I have a created a Acc Seq and I have maintained a table A635 in it, Right now my query is how to make a particular field as optional in it, Say I want to make a distributional channel as optional while creating condition records. How can I achieve it.

Many Thanks in Advance.capture-101.jpg