Employees of a public charter schools: Are public school employees, as defined in Education Article, §§ 6-401(e) and 6-501(g), Annotated Code of Maryland; Are employees of a public school employer, as defined in Education Article, §§ 6-401(f) and 6-501(h), Annotated Code of Maryland, in the county in which the public charter school is located; and Shall have the rights granted under Education Article, Title 6, Subtitles 4 and 5, Annotated Code of Maryland. If a collective bargaining agreement under Education Article, Title 6, Subtitles 4 or 5, Annotated Code of Maryland, is already in existence in the county where a public charter school is located, the employee organization, public school employer, and the public charter school may mutually agree to negotiate amendments to the existing agreement to address the needs of the particular public charter school, including amendments to work days, work hours, school year, procedures for transfers that are consistent with the instructional mission of the school, and extra duty assignments.