There isn't a formal one; reopen voting privileges are granted based on demonstrated experience with the site and subject (measured approximately by reputation), and not having gained the close/reopen voting privilege means not getting a say in such things yet.
That said, there are two informal ways:
You can in theory flag a closed question for moderation attention, but that's only useful in exceptional cases where something has clearly gone wrong, and moderator intervention is needed. For the more normal case of just wanting to cast a reopen vote and not having one, a mod flag would likely be declined in favour of letting close/reopen voters take care of it.
Ask for input on Meta
You can also make a case for reopening on Meta. This is useful for odd corner cases where it's not obvious why it should be closed/open, and the community can chew on it to figure out the best treatment for the question. That might be useful in this case.
(This question here is too general to inspire that kind of conversation though; a meta of that kind needs a specific line of reasoning or description of the problem or corner case that's causing concern for the community to engage with it productively. For example, it may not be obvious to others how there could be an answer unique to D&D 5e; bringing that up directly as an example of how they're different questions might be productive.)