Set style for part of paragraph

[meileetan]

I have set my header to pick up the text from a specific style called Project Name.
In a later paragraph, I have this text:
Project Name: Training Attendance Interface



I tried to set only the text "Training Attendance Interface" to the style Project Name but Word automatically also sets this style to the text "Project Name:". Thus, my header will display "Project Name: Training Attendance Interface" instead of my desired text of "Training Attendance Interface".

How can I fix this?