Sell MAX and Edit Sell option

I’d like a ‘MAX sell’ feature so that while am buying ‘the dip’ I don’t have to cancel an order and recreate the ‘sell’ with the allocation of more shares. I’d like this done automatically in the background for me, i.e. cancel and resell.

If I haven’t set the MAX sell and just the regular sell for x shares not the full allocation, then that just works as it does now.

Also editing a sell might also be a nice feature, I edit the number of shares or the price I want without having to cancel it etc.