A técnica disse que o botão foi trocado em cinco minutos.

In this sentence, a técnica is the feminine form meaning the (female) technician.
Portuguese técnica can also mean technique, but the context (someone said something) strongly points to a person here.
If the technician were male (or unspecified but grammatically masculine), you’d use o técnico.

Que is the normal connector meaning that after verbs of saying/thinking: disse que = said that.
In standard Portuguese, you generally don’t drop que the way English sometimes drops that.

Because ser + past participle is the typical pattern for a passive event (an action done to something): was replaced.
If you wanted to emphasize the resulting state, Portuguese often uses estar: o botão estava trocado (less common, and sounds odd here), or more naturally something like o botão já tinha sido trocado depending on meaning.

Past participles in the passive agree with the noun they describe.
Botão is masculine singular (o botão), so you use trocado.
If it were a peça (feminine), you’d say a peça foi trocada.

Trocar can mean to change, to replace, or to swap, depending on context.
With something like a button/component, trocar o botão is commonly understood as replace the button.