VBA - Message Box With More Than One Output?

I am running a macro in Excel that when runs opens a message box that asks you to enter a start date, then and end date - this works perfectly.

However, what I now need to look at is adding a message box BEFORE these two fields that asks for a Sales Account Refrence number.

Once this number has been entered it then runs the date range boxes against that number entered.

Below is my code that currently works for the date boxes.

It is running a SQL string and the Sales Account Rerefence number is a field called org.sales_acc_ref

Sub GetData()
Dim create_timestamp As Date
Dim response As String[code].....