The customer asks from the job
Pickup, swap, dump and return, or relocate. They pick one, add a note, and send it from their project link.

"It's full. Can you come get it?" A swap request should take ten seconds to handle. Instead it's a voicemail, a callback, a "which job?", and a sticky note. Let the customer ask from the job itself.
A contractor who waits two days for a swap calls the other guy next time.
When a request comes in by voicemail, you fill in the details from memory. Sometimes memory is wrong.
A pickup request that never got written down is a can earning nothing on someone's driveway.
Pickup, swap, dump and return, or relocate. They pick one, add a note, and send it from their project link.
Requests lists each one with the project, the can, and who sent it. Accept and schedule, and the customer gets a text with the window.
Deliver the replacement, remove the full can, empty it, return it to the yard. The driver sees each step. You see where the job is.

Yes. The request waits in your list for the morning. The schedule doesn't change until you approve it.
Yes, with a reason. The customer is told.
Yes. If the driver's truck can't carry the incoming size, the schedule flags it.
Bring a real week: the addresses, the cans, the drivers. We'll set it up on a call and you'll see your day plan before we hang up.