Short answer. Yes. Rule 3, Section 14 of the Rules of Court provides that when the identity or true name of a defendant sued as an unknown owner is discovered, the pleading must be amended accordingly. Now that you know who they are, you are required to amend your complaint.
What the law says
Whenever the identity or name of a defendant is unknown, he may be sued as the unknown owner, heir, devisee, or by such other designation as the case may require
Rule 3, Section 14 — Unknown identity or name of defendant. Read the full provision →
What the law says
when his identity or true name is discovered, the pleading must be amended accordingly.
Rule 3, Section 14 — Unknown identity or name of defendant. Read the full provision →
Yes, amendment is required once the name is discovered
Section 14 answers this without leaving it to your discretion: when his identity or true name is discovered, the pleading must be amended accordingly. The word must makes this an obligation, not an option you can decide to skip now that the more pressing problem, not knowing who to sue, has already been resolved in your favor. The amendment is also what makes the record identify the person the judgment is meant to bind, rather than a placeholder description.
The rule that let you sue as 'unknown owner' in the first place
Section 14 is also what allowed your original complaint to proceed at all despite not knowing the defendant's name: whenever the identity or name of a defendant is unknown, he may be sued as the unknown owner, heir, devisee, or by such other designation as the case may require. That designation was a placeholder the rule permits precisely because the amendment duty exists to correct it once the real name surfaces.
The two halves of the rule work together
Read together, Section 14 is not simply permissive about suing an unknown party; it pairs that permission with a corresponding duty to fix the pleading once the unknown becomes known. The designation was never meant to be permanent. It exists to let the case start, on the understanding that the pleading will be brought into line with the true facts as soon as they are discovered.
What this means for your complaint
Now that you know the defendant's true identity, Section 14 requires you to amend your complaint to reflect it, replacing the unknown-owner designation you originally used. This article does not itself spell out the mechanics of filing that amendment, but it leaves no room to treat the correction as optional once the name has become known to you. Until then, your pleading continues to describe a person who no longer matches what you actually know.
Why the rule insists on this rather than leaving the designation as is
Leaving a defendant identified only as an unknown owner, once the real name is known, would leave the record out of step with reality, which is exactly what Section 14 is designed to prevent. The rule treats the unknown designation as a temporary accommodation for a genuine gap in your knowledge, not as a substitute for the defendant's actual name once that gap has closed.