Here are the steps to regrout a shower:
1. Remove the existing grout using a grinder or a grout rake.
2. Thoroughly clean the grout lines.
3. Manually remove any remaining grout.
4. Thoroughly vacuum the area.
5. Prepare the grout mixture.
6. Apply the grout mixture to the tile with a grout float.
7. Clean the grout and tiles with a sponge.
8. Use a grout shaper to finish off the joints.
9. Remove the existing grout haze and let it dry.
I hope this helps! Let me know if you have any other questions or if there's anything else I can help you with.
[Here](https://homearise.com/regrout-shower/) is a link to a more detailed tutorial on how to regrout a shower that you might find helpful.
