How do I switch player characters mid-gameplay?

Hello, I am fairly new to Unreal 4, I am currently working on a twin stick shooter playable character, the movements and shooting mechanics are done, but I am having trouble on another mechanic:

During gameplay the player is able to change the size of their ship at the press of a button to overcome certain obstacles or enemies, however I am not sure how to achieve this and I can’t find any clear enough tutorials to help, all I have been able to find is how to “possess pawns,” but my character needs to transform between 3 sizes.

I have 3 models set up, all I need to know is how to switch between them mid-gameplay, any help would be appreciated, thanks.

You can Change the size from your mesh with set actor scale 3d.

Have a look her:

This was unbelievably helpful, thank you. I had no idea it was this easy.