You decide to file a claim of lien and you ask your bookkeeper to tabulate the exact amount still owed on the job. With the numbers in hand, you timely prepare and file your Claim of Lien. You then receive a past due payment notice from one of your suppliers showing that you still have another amount pending on this job. What can you do? You already recorded your claim of lien. Can you file an amendment to that claim of lien you already filed? If the time for filing the original claim of lien has not expired, then yes, you can file an amendment. It must be marked as an amended lien, reference the original claim, and include the recording information of the already filed claim.
The same rule applies if the amendment is to correct any sort of other error in the claim of lien – a misspelled name, an incorrect legal description, or the like. The critical issue remains timing – are you still within that allowed timeframe for filing the original lien.
To be clear, this is not the same scenario as you having a second contract for work at the same project. That additional work done under a new separate contract would require its own separate lien claim.