#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
#include <unordered_map>
using namespace std;
#define fi first
#define sc second
#define mkp make_pair
#define pii pair<int,int>
typedef long long ll;
const int N=105,M=10005,oo=1e9;
inline int read() {
    int x=0,flag=0;char ch=getchar();
    while(ch<'0'||ch>'9') {flag|=(ch=='-');ch=getchar();}
    while('0'<=ch&&ch<='9') {x=(x<<3)+(x<<1)+ch-'0';ch=getchar();}
    return flag?-x:x;
}
inline int mx(int x,int y) {return x>y?x:y;}
inline int mn(int x,int y) {return x<y?x:y;}
inline void swp(int &x,int &y) {x^=y^=x^=y;}
inline int as(int x) {return x>0?x:-x;}

int n,m,a[N][N],tot,fr[N][N];
char s[N];
int hd[M<<1],num,qwq[M];
struct node {
    int nxt,to;
}e[M<<2];
#define v e[i].to
inline void adde(int x,int y) {
    e[++num]=(node){hd[x],y};
    hd[x]=num;
}
inline bool chk(int x,int y) {
    return !(a[x][y]==a[x+1][y+1]&&a[x+1][y]==a[x][y+1]&&a[x][y]!=a[x][y+1]);
}
inline void work1(int x,int y) {
    if(a[x][y+1]&&a[x+1][y]&&a[x+1][y+1]) {
        if(a[x][y+1]==a[x+1][y]&&a[x][y+1]!=a[x+1][y+1]) {
            if(a[x+1][y+1]==2) adde(fr[x][y]+tot,fr[x][y]);
            else adde(fr[x][y],fr[x][y]+tot);
        }
    }
    if(a[x][y]&&a[x+1][y]&&a[x+1][y+1]) {
        if(a[x][y]==a[x+1][y+1]&&a[x][y]!=a[x+1][y]) {
            if(a[x+1][y]==2) adde(fr[x][y+1]+tot,fr[x][y+1]);
            else adde(fr[x][y+1],fr[x][y+1]+tot);
        }
    }
    if(a[x][y]&&a[x][y+1]&&a[x+1][y+1]) {
        if(a[x][y]==a[x+1][y+1]&&a[x][y]!=a[x][y+1]) {
            if(a[x][y+1]==2) adde(fr[x+1][y]+tot,fr[x+1][y]);
            else adde(fr[x+1][y],fr[x+1][y]+tot);
        }
    }
    if(a[x][y]&&a[x][y+1]&&a[x+1][y]) {
        if(a[x][y+1]==a[x+1][y]&&a[x][y+1]!=a[x][y]) {
            if(a[x][y]==2) adde(fr[x+1][y+1]+tot,fr[x+1][y+1]);
            else adde(fr[x+1][y+1],fr[x+1][y+1]+tot);
        }
    }
} 
inline void work2(int x,int y) {
    if(a[x][y]&&a[x+1][y]&&a[x][y]!=a[x+1][y]) {
        if(a[x][y]==1) adde(fr[x+1][y+1],fr[x][y+1]),adde(fr[x][y+1]+tot,fr[x+1][y+1]+tot);
        else adde(fr[x+1][y+1]+tot,fr[x][y+1]+tot),adde(fr[x][y+1],fr[x+1][y+1]);
    }
    if(a[x][y]&&a[x+1][y+1]&&a[x][y]==a[x+1][y+1]) {
        if(a[x][y]==1) adde(fr[x+1][y]+tot,fr[x][y+1]),adde(fr[x][y+1]+tot,fr[x+1][y]);
        else adde(fr[x+1][y],fr[x][y+1]+tot),adde(fr[x][y+1],fr[x+1][y]+tot);
    }
    if(a[x][y+1]&&a[x+1][y]&&a[x][y+1]==a[x+1][y]) {
        if(a[x][y+1]==1) adde(fr[x][y]+tot,fr[x+1][y+1]),adde(fr[x+1][y+1]+tot,fr[x][y]);
        else adde(fr[x][y],fr[x+1][y+1]+tot),adde(fr[x+1][y+1],fr[x][y]+tot);
    }
    if(a[x][y+1]&&a[x+1][y+1]&&a[x][y+1]!=a[x+1][y+1]) {
        if(a[x][y+1]==1) adde(fr[x][y]+tot,fr[x+1][y]+tot),adde(fr[x+1][y],fr[x][y]);
        else adde(fr[x][y],fr[x+1][y]),adde(fr[x+1][y]+tot,fr[x][y]);
    }
}
int dfn[M<<1],low[M<<1],st[M<<1],top,col[M<<1],co;
bool inst[M<<1];
void tar(int x) {
    dfn[x]=low[x]=++dfn[0];
    st[++top]=x;inst[x]=1;
    for(int i=hd[x];i;i=e[i].nxt) 
        if(!dfn[v]) {
            tar(v);
            low[x]=mn(low[x],low[v]);
        } else if(inst[v]) low[x]=mn(low[x],dfn[v]);
    if(dfn[x]==low[x]) {
        ++co;
        do {
            col[st[top]]=co;
            inst[st[top]]=0;
        }while(st[top--]!=x);
    }
}
inline void print(int x) {printf("%c",(x==1?'B':'W'));}
inline void Clear() {
    for(int i=1;i<=tot;++i) dfn[i]=hd[i]=0;
    dfn[0]=co=num=0;
}
inline void solve() {
    n=read();m=read();
    for(int i=1;i<=n;++i) {
        scanf("%s",s+1);
        for(int j=1;j<=m;++j)
            if(s[j]=='B') a[i][j]=1;
            else if(s[j]=='W') a[i][j]=2;
            else a[i][j]=0;
    }
    tot=0;
    for(int i=1;i<=n;++i) {
        if(a[i][1]==0) fr[i][1]=++tot;
        for(int j=2;j<=m;++j)
            if(a[i][j]==0) {
                if(a[i][j-1]==0) fr[i][j]=fr[i][j-1];
                else fr[i][j]=++tot;
            }
    }
    bool flag=1;
    for(int i=1;i<n;++i)
        for(int j=1;j<m;++j) {
            int cnt=(a[i][j]>0)+(a[i+1][j]>0)+(a[i][j+1]>0)+(a[i+1][j+1]>0);
            if(cnt==4) flag&=chk(i,j);
            if(cnt==3) work1(i,j);
            if(cnt==2) work2(i,j);
        }
    for(int i=1;i<=tot*2;++i) if(!dfn[i]) tar(i);
    for(int i=1;flag&&i<=tot;++i)
        if(col[i]==col[i+tot]) flag=0;
        else qwq[i]=(col[i]<col[i+tot]?1:2);
    if(!flag) {
        printf("NO\n");
    } else {
        printf("YES\n");
        for(int i=1;i<=n;++i) {
            for(int j=1;j<=m;++j)
                if(a[i][j]) print(a[i][j]);
                else print(qwq[fr[i][j]]);
            printf("\n");
        }
    }
    Clear();
}
int main() {
    int TT=read();
    while(TT--) solve();
    return 0;
}