You cannot use a Bonus Action as an Action.

No.  You cannot use a bonus action as an action.

According to published Sage Advice:
Can a bonus action be used as an action or vice versa? For example, can a bard use a bonus action to grant a Bardic Inspiration die and an action to cast healing word?
No. Actions and bonus actions aren’t interchangeable. In the example, the bard could use Bardic Inspiration or healing word on a turn, not both