It's not clear from your post exactly what you are wanting your ComboBox to do.
If you are trying to get the ComboBox to be populated with different worksheet names when the userform initializes then I would suggest using the Userform_Initialize()
Put this in the code for your Userform. Change UserForm and ComboBox1 to match those in your workbook.
This will populate the combobox. Once the user selects the worksheet from the list you can have the ComboBox selection change event handler take whatever action is desired.
If this is not what you were looking for then please explain your needs again.
HTH
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