If you've lost your copy of your lead-safe certificate on a building that has been through lead abatement, call your lead inspector to ask if they can send you a new copy. They are required to keep this on file for a number of years. If you had lead abatement done privately, only your lead inspector would have a copy of this certificate. These certificates can only be issued by a state-certified lead inspector.
If you believe, or know that your building was under a state lead order, you can contact state DHHS to inquire about the status of the lead order, and whether it was cleared. Manchester does not put buildings under order - only the state can.
If you know the building received funding through a lead program run by Manchester, Nashua, or NHHFA, you can contact program staff directly to inquire. Please keep in mind that the individual programs do not keep comprehensive records on lead abatement for their area. They will only have records of properties which they funded, and may not have the certificates on file, because the certificates are generated by inspectors, and not by the programs. You should check the lead-safe housing registry for Manchester for your property before calling, to see if it is listed.