Hi anonymous user, Welcome to Microsoft QnA forum. If I understand your query correctly, you want to know how to switch the database from one tier to other e.g. from DTUs to VCores. Also you want to know the process to migrate from single Database to Elastic pool. Please refer to below details:
1) Migrating from DTU to VCores: Go to Pricing tier as highlighted in the screenshot, then change the tier and click on 'Apply' button, it should be done within minutes. You can move from VCores to DTUs same way.
2) Migrating from Single Database to Elastic Pool(Assuming both have same server):
a) Go to SQL Elastic Pool
b) Select Configure under Settings from left menu
c) You will see 3 tabs, Pool Settings, Databases and Per Database Settings. Select Databases
d) Click on Add Databases, you will see the list of databases available, pick and select whichever database is needed and click on Apply as below. Then click on Save button. This will add database to elastic pool within sometime.
Please let us know if this answers your query.
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