WEEKDAY Formula in Excel

Does anyone know how using 2 different dates (say in cell B9 4/12/20 and in B10 4/20/20) and put the beginning date in cell B19=B9 and then the get a formula in C19 to stop on the first Saturday's date (4/4/20)?

I have created this function to get first date of week as Thursday in ms access form and reports, but this function return first day of week in las month, but I need it will return only current month dates, if current week first day is in last month then retrun first day of week as 1st date of week in current month.

‘current output

‘when 1-10-2018 is selected from date picker it returns 27-09-2018, which is first date of week in last month but I need it will return 1st of month which is selected in textbox.

Function GetFirstofWeek(dtDate As Date)

'GetFirstofWeek = DateAdd("d", dtDate, -(Weekday(dtDate)) + 1)

' Excel formula for this function which is perfect and may be converted to function as required ‘=MAX(B2-WEEKDAY(B2,14)+1, EOMONTH(B2, -1)+1)

GetFirstofWeek = DateAdd("d", dtDate, -(Weekday(dtDate, vbThursday) – 1))

End Function

'For last day of week

Function GetLastofWeek(dtDate) as date

'=MIN(B2+(7-WEEKDAY(B2,14)), EOMONTH(B2, 0))

GetLastofWeek = DateAdd("d", dtDate, (7 – (Weekday(dtDate, vbWednesday)) + 1))

End Function

In this function last date of week must be in current month, if month end on first date of then week will be closed and last date of week will be 1st date of week or days remaining in current week.

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