You would have to amend it and reclassify it as a regular civil limited jurisdiction case. There may be a filing fee involved. I believe the clerk would then set it for a CMC. However, you may have a difficult time locating the tenant to get him served. You may want to dismiss this action and then file a small claims, but you would only be able to sue for up to $7,500, and you would still have the problem of finding him. You should check your local rules as to what your court does when possession is no longer at issue in a UD. Hope that helps.
It appears the tenant has not been served yet, so you can amend the complaint by filling out a generic complaint for breach of contract. You will lose the speedy hearing when you no longer need to obtain possession. You will keep the same case number in order to avoid payment of another filing fee. Perhaps, you can continue the original case and simply tell the judge possession is no longer an issue. Good luck.
Since you are unable to locate your tenant, you may ask the court for permission for publish your summons in the newspaper. To do this you must complete an “Ex Parte Application for Order for Publication of Summons,” a “Memorandum of Points and Authorities,” a “Supporting Declaration,” and an “Order for Publication of Summons” for the judge’s signature. You must also obtain declarations from anyone else involved in the search for the other party. There are no fill-in-the-blank forms for these documents. So, you most likely have to hire an attorney.
Most often the reason a request for Publication of Summons is denied is because the court does not feel that adequate steps have been taken to attempt to find the person to be served. If the court grants the order to publish, however, your next step is to publish the Summons in a newspaper of general circulation in the location where the party was last known to reside. The newspaper will publish your Summons once a week for four weeks, then provide you with confirmation of publication. Pursuant to Government Code § 6064, service is deemed complete on the 29th day after the first date of publication. If the other party has not filed a response 30 days after the effective date for service, you may file for default against the other party. You will then be able to continue your case without the other party’s participation. I don't know if it is worth your time and money because collecting a judgment is far more difficult than obtaining a judgment.