While you have to choose between the male and female protagonist at first, you later gain the option to freely change gender in Arknights: Endfield at any point - however, among all Xaihi's talk of the Dijiang and its many facilities, she doesn't actually tell you about this.
Luckily, the process is pretty simple, completely free, and you can do it as many times as you want. The only catch is that you can only change the Endministrator's form once every 24 hours, so you'll have to wait a while if you want to switch back.
How do I change gender in Arknights: Endfield?
You unlock the option to change the Endministrator's form during the main Chapter I - Process II story quest, Maintenance Progress, which allows you to board the Dijiang once again. In order to get to this quest, you first need to meet these requirements:
- Reach Authority Level 15
- Complete side quest Restart Area Stock Redistribution
- Complete main quest Chapter I - Process II: Work Preparation
Once you have access to the Dijiang, you follow these steps to change the Endministrator's gender at any time:
- Go to the Dijiang - you can teleport here from any other area by clicking on the 'OMV Dijiang' in the top-right corner of the map
- Head to the room with the Protocol Singularity marker in the Kernel Sector, to the north of the TP point that sits between the Central Ring and the Working Sector (circled in the image above)
- Approach the Stasis Core and select the option to 'Switch Endministrator's Identity'
- Hit confirm
Note that you can only switch the Endministrator's form once every 24 hours, but the process is completely free. This means that you can save all of those handy oroberyls and materials you get from the latest Arknights: Endfield codes to spend on your Arknights: Endfield banner of choice instead!