Planetary capital upgrade to the highest level - multiple possible?

[[POEX]An-Tarxamon]

I have upgraded one planetary capital to highest level, but I want to do the same with others, so I may gain more influence. I conquered one planet, which I control directly, but it gives me no possibility to upgrade its capital.

Is it a mistake? It it possible to have multiple Empire Capital or its equivalent? Thanks in advance for response.

[Rathnaga]

You may only have 1 Empire Capital building.

[[POEX]An-Tarxamon]

Originally posted by Rathnaga:

You may only have 1 Empire Capital building.

Thank you. So, is it any other way, how to gain more influence?

[Vieira]

Tech and declare other nations rivals.

[Lectio Aterus]

For each vassal, you will have +1 of influence, with rivals, technology...

[Elitewrecker PT]

You can only have one Capital-Complex (unless you capture planets with one built)

Originally posted by Meraxes:

For each vassal, you will have +1 of influence, with rivals, technology...

Protectorates give you +1 influence, vassals don't.
Being in an alliance/federation decreases your influence gain.

[[POEX]An-Tarxamon]

Thanks all for their responses.

[Rax Savvage]

some leaders do too, but so far i've found only 1 to do so and she was voted in.

[Elitewrecker PT]

Ye, that's a possible ruler trait