The city may sell or dispose of real property by warranty or quitclaim deed, easement, grant, permit, license, deed of trust, exchange, mortgage, contract of sale of real property, plat dedication, lease, tax deed, vacation, or any other lawful method or mode of conveyance or grant. Any instrument requiring execution by the city shall be signed by the City Manager and attested by the City Clerk or notarized by any notary commissioned in Alaska; provided, however, that any disposal of property through a platting action shall also be signed by the Chairman of the Platting Board or the Director of Planning acting as the Platting Authority.