I bought 2 trash bins and returned one of them.
Is there a way to record cancellation of part of expense?
It has to be recorded on a checking account.

Yes,

Just duplicate the transaction but move half the amount from payment to deposit column.

You can put a note in the memo field to remind yourself what it is all about.

That's assuming you got refunded to your checking account.

If you got refunded in cash then you need to do the same but with your cash account instead.

You can use the same category for both the expense and for the (partial) refund.
When duplicating the transaction, as mbeenham suggests, make sure either to change "withdrawal" to "deposit", or just enter the amount as negative; either way.