edit wpf code that refers to a resource
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i am trying to edit a source code in c#
forms writes with  WPF, and in them don't declare 
properties directly but use from resources in below
i placed some lines from a WPF form .

    <Grid>
        <StackPanel>
            <Label>
                <LocText ResourceIdentifierKey="CustomerName" Suffix=":"/>
            </Label>
            <TextBox HorizontalAlignment="Left" MinWidth="200" Text="{Binding Name}" />
            <Label>
                <LocText ResourceIdentifierKey="GroupCode" Suffix=":"/>
            </Label>
            <ComboBox HorizontalAlignment="Left" MinWidth="150" Text="{Binding       GroupCode,Mode=TwoWay}"
                      ItemsSource="{Binding GroupCodes}" IsEditable="True"/>
            <Label>
                <LocText ResourceIdentifierKey="PhoneNumber" Suffix=":"/>
            </Label>
            <Common:MaskedTextBox HorizontalAlignment="Left" MinWidth="100" InputMask="{Binding PhoneNumberInputMask}"
                 PromptChar=" " UnmaskedText="{Binding PhoneNumber, Mode=TwoWay, UpdateSourceTrigger=LostFocus, ValidatesOnDataErrors=True, ValidatesOnExceptions=True}" />
            <Label>
                <LocText ResourceIdentifierKey="Address" Suffix=":"/>
            </Label>
            <TextBox HorizontalAlignment="Left" MinWidth="200" MinHeight="55" Text="{Binding Address}"
                 AcceptsReturn="True" />
            <Label>
                <LocText ResourceIdentifierKey="Note" Suffix=":"/>
            </Label>
            <TextBox HorizontalAlignment="Left" MinWidth="200" MinHeight="55" Text="{Binding Note}"
                 AcceptsReturn="True" />
            <CheckBox Margin="0,5,0,0" IsChecked="{Binding InternalAccount}">
                <LocText ResourceIdentifierKey="InternalAccount"/>
            </CheckBox>
            <Button HorizontalAlignment="Left" Margin="0,10" MinWidth="70" Content="{Binding SaveCommand.Caption}"
                 Command="{Binding SaveCommand}" />
            <Label Content="{Binding Error}" Foreground="Red" />
        </StackPanel>
    </Grid>

how i can edit an attribute?
for example i want to change content of a Lable. 