I use a voice command to choose a date, yesterday's date, tomorrow, etc... and I want to get this date in a variaable in different formats :

all variable are defined

If ListVar1 = "aujourd'hui" Then DATEPAIEMENTLEFT = ""& Format (Now + 0, "yyyymmdd-")
 If ListVar1 = "d'aujourd'hui" Then DATEPAIEMENTLEFT = ""& Format (Now + 0, "yyyymmdd-")
 If ListVar1 = "demain" Then DATEPAIEMENTLEFT = ""& Format (Now + 1, "yyyymmdd-")
 If ListVar1 = "à demain" Then DATEPAIEMENTLEFT = ""& Format (Now + 1, "yyyymmdd-")
 If ListVar1 = "hier" Then DATEPAIEMENTLEFT = ""& Format (Now -1, "yyyymmdd-")
 If ListVar1 = "d'hier" Then DATEPAIEMENTLEFT = ""& Format (Now -1, "yyyymmdd-")
 If ListVar1 = "il y a 2 jours" Then DATEPAIEMENTLEFT = ""& Format (Now -2, "yyyymmdd-")
 If ListVar1 = "il y a 3 jours" Then DATEPAIEMENTLEFT = ""& Format (Now -3, "yyyymmdd-")
 If ListVar1 = "il y a 4 jours" Then DATEPAIEMENTLEFT = ""& Format (Now -4, "yyyymmdd-")


msgbox(DATEPAIEMENTLEFT & " " & Format (Now + 0, "yyyymmdd-"))

DATEPAIEMENTRIGHT = DATEPAIEMENTLEFT
msgbox(""& Format (DATEPAIEMENTLEFT, "yy.mm.dd"))
DATEPAIEMENTRIGHT = ""& Format (DATEPAIEMENTLEFT, "dd.mm.yyyy")

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1st messagebox work error freee

2nd message box gives "errir 10620 : invalid function argument value

last line too

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Why this error ?

Memory: 16GB Microphone Brand and Model: LFH 4000 & Flexy Mike  Operating System: win 10, latest update; Surface Book 2, Processor (CPU) Type & Speed: I7 8650 Soundcard Brand and Model: none Speech Software: Dragon Medical Practice Edition, french version: 4.2 Using KnowBrainer?:Yes

Double double quotes may be the problem. That turns into an escaped single open or close double quote character to use within a string (itself demarcated by double quotes). So why do you need it? Either put something in the string between the double quotes or exclude it (plus the "&" concatenation symbol since thee is nothing to concatenate anyway).
HTH

PG

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Double double quotes are not the problem (though not necessarily needed either). The variables as assigned are handled as type (string). Format() function varies based on expression type - strings can't be formatted with a date pattern.

*If you need two different date formats mixed as in your example (if not, tweak as needed) - I don't have advanced scripting open, so may not be 100% - give it a try...

DATEPAIEMENT = Now

If right(ListVar1,3) = "hui" Then DATEPAIEMENTFULL = Format (DATEPAIEMENT, "yyyymmdd-") & Format(DATEPAIEMENT, "dd.mm.yyyy")
If right(ListVar1,6) = "demain" Then DATEPAIEMENTFULL = Format (DATEPAIEMENT+1, "yyyymmdd-") & Format(DATEPAIEMENT+1, "dd.mm.yyyy")
If right(ListVar1,4) = "hier" Then DATEPAIEMENTFULL = Format (DATEPAIEMENT-1, "yyyymmdd-") & Format(DATEPAIEMENT-1, "dd.mm.yyyy")
If left(ListVar1, 7) = "il y a " then
njour = val(mid(ListVar1,8,1))
DATEPAIEMENTFULL = Format (DATEPAIEMENT-njour, "yyyymmdd-") & Format(DATEPAIEMENT-njour, "dd.mm.yyyy")
end if

msgbox DATEPAIEMENTFULL