How do I compare tables from 2 separate databases

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SQL

So I have been using an SQL statement that will allow me to use tables from the same database for comparison. Here is the code:

Merge into table1 as T
using [table] as S
on T.[Last Name] = S.[Last Name] and T.[First Name] = S.[First Name]

When Matched then 
Update Set T.[Companynamne] = S.[Companyname];

DELETE T1 FROM [table] T1 JOIN [table1] T2 ON T1.[Last Name] = T2.[Last Name] AND T1.[First Name] = T2.[First name];

I tried to use the same code to compare another table from another database, I kept getting an out of object error.

I would like to use this same code but with modifications, what would I need to change to get the information from the second database as S in the SQL formula and T1 as the delete statement for the same thing?

What I have tried:

I couldn't figure out how to change it to recognize that it's for comparing 2 tables from 2 databases.