% Preamble
documentclass[11pt]{article}

% Packages
usepackage[showdow,en-GB]{datetime2}

% Document
begin{document}
    % Turn off showdow
    DTMlangsetup{ord=raise,showyear=true,showdow=false}
    % Format a date
    DTMdate{2019-01-01}

    % Turn showdow back on
    DTMlangsetup{ord=raise,showyear=true,showdow=true}
    % Format the same date
    DTMdate{2019-01-01}
end{document}