If the request is submitted then you can edit the request as the end user (enable the option in the RO settings) or as an analyst (unlock the SRP using a quick action). You can give analysts quick actions to just update specific SRP's as well with prompt boxes if needed.
Can yo give the example your trying the achieve?
I have a need for this also. Similar to phan10ms's example: I'm trying to include an option field (could be a list, drop-down, or checkbox) and some following fields will be dependent on the option chosen - for visibility, and/or required settings. If they pick an option, fill in some following fields, then decide they picked the wrong option, I need those subsequent fields to be cleared. Even if a subsequent field is another list, dropdown or checkbox.
Is this possible?