Nothing to do with your original question, but you can do the following rewrite

# Exactly equivalent drop-in replacement
sub get_my_params {
    map { defined param( $_ ) ? param( $_ ) : '' } qw(
        ticket title client next_step o_date o_time
    );
}
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However, better would be to rewrite it as

# Returns a hash, not an array
sub get_my_params {
    map { $_ => defined param( $_ ) ? param( $_ ) : '' } qw(
        ticket title client next_step o_date o_time
    );
}

# Use this one as so:
my %params = get_my_params();

if ( $params{ title } ne '' ) {
    # Do stuff here.
}
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The use of a hash is better because you can add new parameters to get_my_params() and the only thing that changes is the new code you add. You don't need to keep track of a bazillion parameter names.