Hi,
You may take/pass AZ-305 exam without having the pre-requisite Microsoft Certified: Azure Administrator Associate (AZ-104 exam) certification, however, you will not earn the Microsoft Certified: Azure Solutions Architect Expert certification until you also pass AZ-104.
In other words, if you want Solutions Architect certification you need to pass both AZ-305 and AZ-104.
Please click Accept Answer if the above was useful.
Thanks.
-TP