There really isn’t a protocol that I am aware of. Receive more ashes or don’t.
If the ashes you already received are still obvious tonight then it might be silly to receive more tonight. But if they are worn away and singing won’t interfere with receiving more then why not?
DISCLAIMER: Catholic Answers has turned over the archive to Catholic-Questions.org and no longer owns, manages, or moderates the forums. For additional apologetics resources please visit www.catholic.com.