Hy, i have this formula :
=IF(B5<"",IF(ISNA(VLOOKUP($B5,PLANNING!$B$4:$G$59 3,6,FALSE)),"??",VLOOKUP($B5,PLANNING!$B$4:$G$593, 6,FALSE)),"")

"PLANNING" = an tab name.
I need something like this ( "A1" instead of "PLANNING":
=IF(B5<"",IF(ISNA(VLOOKUP($B5,A1!$B$4:$G$593,6,FA LSE)),"??",VLOOKUP($B5,A1!$B$4:$G$593,6,FALSE)),"" )

"A1" = cell
And in "A1" to write an tab name. (planning ; monday ; tuesday...etc)
"A1" content to replace "PLANNING" from formula.


Thanks in advance!