Edit Excel database through UserForm based on combobox Selection

I Have a VBA userform to enter Titel(A), Doctors name(B), Address(C), Area(D), Area Code(E), Number of patients(F), and Business(G) into sheet3('Master")
(clm A to G) with
combobox2, Row source sheet 2 ("Teritory") for C5:c7 to select Title (Dr., Mr or Shop)
TextBox1 For Doctor, shop or Persons name
TextBox2 For Address of the Doc, shop or person
Combobox3 for Area (Row Source Teritory!a3:a60)
Textbox3 for for Area Code (A Vlookup value form Teritory!B3:B60)
Textbox4 for Number of patient
Textbox5 For Business

Commandbutton1_Click() adds data to sheet3("Master") perfectly.

Now i want to edit the data stored in sheet3("Master"). using the same userform
I have added a Combobox1 to find Doctors Name (Clm B of sheet3("Master")) Row Source Master!B2:B4000(assuming the data should to be more than 4000 doctor)
I am stuck with three specific problem

One:
Can any one help me to find duplicate Name in this Combobox1 (coz there are several Doctors or shop with same name, like Dr. A K GHosh, Lokenath Medical etc) currently my Combobox1 shows only 1st name, if same name comes twice it fail to find the second duplicate Name ( if I type A K Ghosh it only shows 1st A K Ghosh, The Second or Third A K Ghosh Never comes although it is there in the list)

Two:
how to populate textbox and combobox of my userform1 from sheet3("Master") depending upon the value selected on combobox1.

Three:
how to edit and save the data again in to corresponding row of sheet3("Master")

Thanks in advance
surajit

any suggestions or guidance at all would be greatly appreciated. Thank you!