My guess is that you'd likely have a better chance thru the channels website (Netflix.com, HBO.com etc) than thru the Roku platform. With that said, it also wouldn't surprise me if some channels just aren't set up for that, and only allow or have automated, recurring billing, not manual intervention, but you can see. Possibly email them if they don't to ask.
Also, not for nothing but this really is the wrong section for this thread. Possibly this section: https://community.roku.com/t5/Accounts-Billing-Orders/bd-p/accounts but again, I'd suggest going thru the channel or service directly if you can, otherwise try that section as Roku staff tends to respond in those threads. We're just indie channel producers. 'The Land Of Misfit Toys' of the Roku stratosphere.